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FAQs on Tapwater Filtration: Reverse Osmosis, Deionized, Distilled Water Systems Installation, Maintenance & Repair

Related FAQs: RO/DI & Distilled Water 1, RO/DI & Distilled Water 2, RO/DI & Distilled Water 3, RO/DI & Distilled Water 4, RO/DI & Distilled Water 5, RO/DI & Distilled Water 6, RO/DI & Distilled Water 7, Rationale, Selection, For Commercial/Large Output, RO Water Storage, RO Water Treatment, Deionizing Source Water Filtration, Kati-Ani DI Units, Kent, Kold-Steril Units, Water Make-up, Nitrates,

Related Articles: Water Purification Using Reverse Osmosis, Reverse Osmosis, A Multipurpose Tool By Mark E. Evans, Water Changes, Water Quality, Synthetic or Natural Seawater, Nitrates,

Again, the best indication of water quality/suitability? Your careful observation of your livestock's appearance and behavior. Caesio cuning (Bloch 1791), the Red-Bellied Fusilier. A whole family of fishes not used in our interest...

RODI; unit not working w/ membrane renewal        5/8/17
<Hi Devin>
Just a quick question on RODI. I have been using a 35 GPD six stage system for about five years.
I just changed the 35 GPD membrane to a 75 GPD membrane. I fired it up and it has been running for 30 minutes, dispensing waste water, but no filtered water. It has been a long time since I initially set this up. I have
changed other filters but never this one. Is this a normal amount of time to wait for filtered water?
<Mmm; something is wrong here. I would turn off the water and carefully retrace all lines... with your supplied instructions or online copy... Making sure each line is attached, going where it should be. Did the new membrane come with a sleeve on it? Did you remove this plastic? >
<Welcome. Bob Fenner>
Re: RODI       5/8/17

Hello Bob
Yes, I removed the plastic. Per your advice I went thru all the connections to make sure they were secure. Started it up again and now water is flowing! Thank you much.
<Ahh; possibly an air lock. Congrats. BobF>

R/O unit; coming out of years storage      1/16/17
I stopped using my R/O / DI unit for about 3 years, I just shut off the water supply to the unit, so I assume it still has some water in it, I started it up again this week, my question is what are the issues with a unit sitting this long without use, do I need to change the membrane <Mmm; perhaps; but if it were me/mine, I'd simply test the effluent/filtered water for TDS, chlorine... even just pH. Likely if you have a carbon contactor there is no need to change out the other
and filters, what about the DI canisters, would the those be ok. I flushed the unit for 1 hour and the TDS was zero on the outgoing water.
<Oh! You're golden then. No worries>
not sure if this means its ok. is there any other tests I should do to confirm water is ok, a little confused.
thanks for your help.
Val Sammut
<Welcome. Bob Fenner>

cycling of saltwater aquarium; RO malfunction          4/7/15
I’ve cycled many tanks over the years but have never dealt with this particular issue before. I live in an agriculture state now ,but was a recent move. I have an ro filter hook-up for drinking water which I used to fill the tank after taking a sample to PetCo for them to test the water .I did not have testing kits yet. I was told all was well ,
so I went ahead and filled the tank, and began a fishless cycle. I added ammonium chloride to the tank, waited a few days to test with my new SeaChem test kits. I did not initially get a free ammonia level, but did get a total ammonia level of 0.5- 1.0. It’s hard to decipher the gradual color changes. Even though I figured it was too early to get any reading from nitrite, nitrate testing
<For browsers and you; I WOULD be adding some other "feeder stock"; likely at least a proteinaceous food AND a bacteria culture of use>

I did that along with ph and alkalinity testing. I was surprised to find the water testing positive for both nitrite and nitrate at 2 and 20ppm respectively so soon.
<Mmmm; again... some other source>
Long story short there is both the same numbers in the ro filtered water
<?! Should NOT be coming through an operating RO device>

I had coming from the tap. Now I have to try to figure out is this tank cycled once the total ammonia and nitrite levels go to zero?
<Should be>
It’s a 90 gallon tank and I’d hate to drain it and refill so I plan to use a product called az-no3
<A real product. I.e.; it works>
to get rid of excess nitrate that’s in the tank after cycle and before any thing living goes in and the get ro/di unit to do water changes from then forward.
<I'd look into adding at least an activated carbon contactor module to your string... that is, another step in your Reverse Osmosis tool>
Right now I’m getting sporadic free ammonia readings (sometimes 0.2 or so , sometimes zero) and a consistent total ammonia reading of 0.5 every few days when I test. Nitrite and nitrate still holding about the same at above mentioned numbers and I’m about 1 1/2 weeks into the cycle (which is still way early, I know and understand that). I just wondered if there is going to be a drop in the nitrite since it’s not being converted but pre-existing in the water?
<A few things else may be going on here... the source, type of nitrogenous (and other) compounds in your source water that are evidently getting past your RO... I really just urge what has been stated above. The addition of flake or pelleted food likely; AND a real aquarium-beneficial mix of microbes; ala Dr. Tim's, Microbe-Lift, SeaChem...>

I’m sorry if this seems like a silly question ( I’m not the best with chemistry) and wanted a second opinion on what to expect.
<Not silly; actually profound>
90 gal. corner bow
Aquamax cones protein skimmer HOB
Hydor 600 canister filter
2 Hydor powerheads for circulation
instant ocean reef crystals as salt mix
3 inch sand bed
no rock as of yet (plan to get life rock once cycled, has bacteria in it from what I gather)
<Oh! The rock can sub for both the food and bacterial additions... just a few lb.s
Thanks Gail
<Welcome; Bob Fenner>
Re: cycling of saltwater aquarium          4/7/15

Hi Mr. Fenner,
Thank you for your quick reply and I have solved the mystery of the faulty water!
After receiving your email last night I decided to test the regular tap (unfiltered) and there were no nitrites and maybe 1ppm nitrate in that water, so I have to conclude that my filter was installed incorrectly or backwards!
If I hadn't decided to start up a tank and had not contacted you it may have been quite awhile till I noticed anything amiss. I will now contact the company and find out how to fix this mess along with the handyman who installed it and give him a piece of it. I may also have to drain tank after all if anything worse that nitrite and nitrate got flushed into that water.
<I'd just wait at this point... the little bit in there presently is of little consequence>
If they give me a breakdown of the chemical composition of the water and I'm not sure if it should stay or go I
may call upon your expertise to say yea or nay, if that's ok with you.
For right now until I have the facts everything will be in stasis. Thank you for possibly saving mine and my family's life, we are so very grateful you do what you do!
Thank you, Gail
<Very glad to be of assistance. Bob Fenner>

RO unit      3/21/15
Hello Crew, I am working on setting my saltwater tank and I bought a RO unit. When I opened the unit and looked at the directions it said that I would need to use a preservation fluid on the membrane in between uses.
Is this necessary? Also where would I get this fluid/which would you recommend? Thank you, Blake
<Guess I'm behind the times (again; as usual); never heard of such a thing.
Will you be using the unit continuously... i.e. daily, for other/potable uses? If so, I would not be concerned... I suspect there is some sort of "after market/ing" here... with some concern that the tris membrane might somehow be damaged by.... ?
Bob Fenner>
Re: RO unit

Thanks for the quick reply, Bob. I only plan on using it for top offs/water changes.
<Ahh; thanks for sending along the pertinent bit of written instructions.
Again; for this application, no worries>
Thank you and have a nice day,
Blake Hicks
<And you; Bob Fenner>

Ro/DI (coral life pure flow 2). Repair    10/7/14
I recently discovered that my new Coralife pure flow 2 ro/DI system only seems to be filling the micron canister with water. I have been experiencing some water quality issues in my reef tank and think this might be the cause.
Do you have any idea why this may be happening?
<Mmm; yes. Usually a matter of the plumbing being installed incorrectly.
Secondarily by a tris membrane failure. There are some lesser causes additionally. I'd be contacting Coralife re>
I searched the faq and user guide and didn't find an answer.
<Bob Fenner>

RO/DI unit not producing product water after filter change     8/25/14
Hi all,
I'm having an issue with my Kent Hi-s RO/DI unit. A few days ago I changed the filters in the unit but since doing so it has not produced a drop of product water. I tried(numerous times) re-seating the membrane. The flow restrictor is still present and looks ok. I even tried putting the old filters back in but that didn't work either.
<Mmm; something (a valve... likely white colored w/ a blue handle) is turned off here.... take the entire unit out where you can look at it (hopefully the tubing is long enough to allow this) and have a look/see to
assure none of the shut offs are "at right angles">
I did notice that if I remove the filter from the 3rd canister I get a pretty strong stream of water from the product line. With the filter in the 3rd canister, the canister will fill with water but no product water
will come out..
<IF you find it hard to locate the occlusion... I encourage you to (starting from the discharge end) to undo and reseat the compression couplings of the tubing for the unit)
Can someone give me ideas on what to look at..The water level in my tank is starting to get low :(
<Do write back if this isn't clear or doesn't solve the issue. Bob Fenner>
Re: RO/DI unit not producing product water after filter change
Thanks for responding!
I took the thing apart today and looked for anything that could be a valve but didn't see anything. And while putting it back together I reseated the compression couplings. However that didn't seem to do anything and it is still not producing any product water. I'm totally at a loss on this
<Mmm; dang... hard to describe the procedure here... w/o having the unit in hand. IS there a fish store nearby you can take it into? Are you willing to ship it to Kent for them to have a look/see? BobF>

Re: skimmer... plus now... RO maint.       7/18/14
Thanks as always, Bob
From the reading I did, of course after buying this skimmer, is the bigger diameter body and neck, the more organics, volume, you need to sustain a foam head that drives the organics out.
I will leave it in there, cant really justify buying another skimmer to experiment.
Lastly, I have always changed it at 001, others say 015, but when would you safely change the ro unit membrane when using a tds meter?
<Depends on the application... either number for TDS is fine IMO/E... cheaper to use per gallon by letting the value go higher>
Mine has went to 008, hoping to squeeze more life out of it. What's your thought?
<Likely posted... B>

Phosphates... really/and algae control; RO maint. 02/13/13
Hi crew,
I am having an issue that I can't pinpoint and I was hoping maybe a third-party perspective could help find the source of my problem. I am having issues with brown hair algae in my 75gallon (year and half old)  reef. I know that in order for algae to thrive it requires the presence of nutrients in the water.
<Among other pre-disposing factors... such as a lack of competition, predation, low circulation, low RedOx, DO...>
 All my parameters are in check except for phosphates. I am using a Red Sea test kit and the water from my tank is showing .8ppm of phosphate.
I figured now that I know what my issue is I need to work on my nutrient export. For the last 3 months I have been doing 10 gallon water changes every week religiously.
<An expensive and slow means... dilution>
Every month I am removing 40 gallons of water which is about half the water volume (I also have a small sump). I have been removing filter socks regularly, blasting the rocks during water changes to syphon out detritus and physically removing the algae from the rocks.
<And, as the saying goes: "How's that working out for you?">
I started to see a bloom of coral line algae begin to grow on the rocks and the algae starting to die off. Great! I kept up my water changes.
After a water change three weeks ago. I got a huge bloom of algae again.
I was so disappointed. I looked at my RO/DI unit and figured maybe I would need to change the media out even though my TDS meter shows no traces. I ordered up the media and skipped my water change last week.
The algae began to die again. MY media came in and I was making water yesterday for a water change. I got curious and tested the water coming out of my RO/DI for phosphates and low and behold it was reading .8ppm.
How could this be?
<Mmm, faulty membrane/s, bad carbon in the contactor...>
What else can I possibly do to treat my water?
<Quite a few things actually, but I wouldn't go this route... I'd focus on other means...>
I use an Aqua FX Barracuda RO/DI. The membrane is not even a year old and the other media is brand new as of yesterday. I made around 20 gallons of water yesterday and I could see the DI cartridge was already that rusty color at the top of the cartridge from just making 20 gallons. I have a TDS meter installed on the unit and can see that the meter is picking up traces coming into the unit and then as it exports it I get the 0 reading.
I am basically introducing the phosphates into my tank in the form of water changes and cap-offs.
<And foods>
I have no fish in the tank at the moment.
<Oh, not much food then>
 I only have inverts in the forms of a few corals, shrimp and a reef lobster. What do you suggest?
<That you read here: http://www.wetwebmedia.com/avoidingalgaeproblesm.htm
and as much of the linked embedded and sorted files at the top that you consider prudent... and consider a long-term approach, solution... Adding a DSB in a sump, live macro-algae in there/a tied in refugium, on a RDP timed lighting scheme. Bob Fenner>

Setting up an RO system 1/27/12
Bob, As I thought and I don't suppose putting a bung in the outlet and packing with epoxy resin would work would it?
<Mmm, would... but a threaded thru-hull w/ a plug (all PVC or ABS) would be my preference>
A couple more questions about RO systems to which I can find no clear answers.
1. I intend to fit an automatic shut off float valve to halt the water entry (rather than the exit) into the RO and above that an overflow to waste. In worst case scenario I.e. float valve failure then what sort of size overflow would handle the mains pressure water and carry it all to waste drain?
<... very small likely... but I'd get one that could/would handle the flow if the whole end of the device sheared off. I referred you to ScottV's article re some time ago>
2. SpectraPure says a booster pump will make the membrane more efficient and prolong the life of the membrane . How can the. pump as well as the RO be shut off?
<A few ways... best to have a float switch that will cut power to the pump>
Is it to do with the float valve being switched as opposed to un-switched?
<A separate switch>
And what is the switch?
<What do you mean by this? A simple electronic or mechanical/cam will do>
Also there are a number of pressure valves for a shut off some operating at 40% and others at 90% of mains pressure. Are these pressure valves differences dependent upon or related to the auto shut off being switched or not and/or whether or not a booster pump is employed?
<Don't know what you're referring to here>
3. A automatic flush valve is required or so says the boss of SpectraPure otherwise the warranty is voided. The flush valve is or doesn't look like it's automatic as in some other systems.
<It is>
So he further recommends that at the end of it's running time the flush valve ought to be operated ~ presumably a timer Is needed here and so it could be called automatic
<Mmm, no; are pressure differential related>
4. The boss go on to say that you must de-gasify ( an American nonsensical invention which means I think allowing the gas (CO2) to dissipate or escape to atmosphere) the system before the water enters the DI to prevent the build up of CO2. Now just how do you do that?
<Not necessary... and are you sure you just don't want to use RO alone? I would and do>
5. Float valves prices vary enormously. Are there any benefits to buying an expensive one?
<Not really>
As marriages turn to divorce on about the third flood you'd think we'd buy a better one if such existed. Does it?
<Better, but not best>
Sorry Bob for so many daft questions but I aim to have me a wondrous tank and I sure wont get it if I don't set it up right in the first place. I know it's somewhat ambitious and so I must take it step by step.
<I think you're over-reaching here. Try to keep all in perspective. Who knows? Perhaps a meteorite will come through your ceiling! B>
Re: Setting up an RO system 1/28/12

Unfortunately I am on a tight schedule. To do the things I want to do..... overreaching I may be but I figure,....., well this poem might say it and its got meteors......besides as soon as my brain catches up with the information that I have overloaded it with I will not be overreaching. and more besides overreaching only applies if you give up or are defeated neither of which is likely in my case. Perspective will follow understanding which means work.
Don't push that to the dailies please.
<Have deleted>
Now back to business.
* why RO only? I thought the DI cleared phosphate?
<RO will remove most all and some HPO4 is vital>
* will measure the garden tap (no flow restriction) output tomorrow and it will be more than I think, I think. Then I can work it out to Scotts number.
* switch ? I meant solenoid or such like.
<Cheers, B>
Setting up an RO system 1/27/12

Bob, As I thought and I don't suppose putting a bung in the outlet and packing with epoxy resin would work would it?
<Mmm, would... but a threaded thru-hull w/ a plug (all PVC or ABS) would be my preference>
A couple more questions about RO systems to which I can find no clear answers.
1. I intend to fit an automatic shut off float valve to halt the water entry (rather than the exit) into the RO and above that an overflow to waste. In worst case scenario I.e. float valve failure then what sort of size overflow would handle the mains pressure water and carry it all to waste drain?
<... very small likely... but I'd get one that could/would handle the flow if the whole end of the device sheared off. I referred you to ScottV's article re some time ago>
2. SpectraPure says a booster pump will make the membrane more efficient and prolong the life of the membrane . How can the. pump as well as the RO be shut off?
<A few ways... best to have a float switch that will cut power to the pump>
Is it to do with the float valve being switched as opposed to un-switched?
<A separate switch>
And what is the switch?
<What do you mean by this? A simple electronic or mechanical/cam will do>
Also there are a number of pressure valves for a shut off some operating at 40% and others at 90% of mains pressure. Are these pressure valves differences dependent upon or related to the auto shut off being switched or not and/or whether or not a booster pump is employed?
<Don't know what you're referring to here>
3. A automatic flush valve is required or so says the boss of SpectraPure otherwise the warranty is voided. The flush valve is or doesn't look like it's automatic as in some other systems.
<It is>
So he further recommends that at the end of it's running time the flush valve ought to be operated ~ presumably a timer Is needed here and so it could be called automatic
<Mmm, no; are pressure differential related>
4. The boss go on to say that you must de-gasify ( an American nonsensical invention which means I think allowing the gas (CO2) to dissipate or escape to atmosphere) the system before the water enters the DI to prevent the build up of CO2. Now just how do you do that?
<Not necessary... and are you sure you just don't want to use RO alone? I would and do>
5. Float valves prices vary enormously. Are there any benefits to buying an expensive one?
<Not really>
As marriages turn to divorce on about the third flood you'd think we'd buy a better one if such existed. Does it?
<Better, but not best>
Sorry Bob for so many daft questions but I aim to have me a wondrous tank and I sure wont get it if I don't set it up right in the first place. I know it's somewhat ambitious and so I must take it step by step.
<I think you're over-reaching here. Try to keep all in perspective. Who knows? Perhaps a meteorite will come through your ceiling! B>
Re: Setting up an RO system 1/28/12

Unfortunately I am on a tight schedule. To do the things I want to do..... overreaching I may be but I figure,....., well this poem might say it and its got meteors......besides as soon as my brain catches up with the information that I have overloaded it with I will not be overreaching. and more besides overreaching only applies if you give up or are defeated neither of which is likely in my case. Perspective will follow understanding which means work.
Don't push that to the dailies please.
<Have deleted>
Now back to business.
* why RO only? I thought the DI cleared phosphate?
<RO will remove most all and some HPO4 is vital>
* will measure the garden tap (no flow restriction) output tomorrow and it will be more than I think, I think. Then I can work it out to Scotts number.
* switch ? I meant solenoid or such like.
<Cheers, B>
Re: Setting up an RO system 1/30/12

A 1" bulkhead on average will flow 350gph. My garden tap fully open delivers 3 gallons (US) per minute which is 180gph so the 1" is fine but 3/4" is not as rated 165gph.
<About right>
What follows sounds stupid. I just cant figure out how and where and what the stupidity is
A LiterMeter III does away with float valves, enables auto shut off, automatic top off, automatic water change and as it's a peristaltic pump so relative heights are not critical . Is that right?
The water container next to the RO unit say under the sink contains your RO water is to have two floats and a 1" overflow.
Can you have both the RO unit running, filling the water container and the LiterMeter auto top off working drawing off this same container for the auto top off function.
<Can have both>
Or are you obliged to separate handling the production of RO water from handling the storage of RO water. .In that case I would need separate reservoir. for top off and obviously a salt water reservoir.

Water Filtration, RO gear... anomaly, trouble shooting 3/22/11
Hi folks!
Thanks so much for all your help, past and future.
<Welcome then and...>
I've been struggling with my water. Currently I have 3 (!!) RO/DI systems hooked up in my fish room, and the three of them working together only produce about 5 gallons of filtered water per day.
<By "working together" I'll assume in parallel, not series>
I started the normal way--bought one system, hooked it up. It worked for a month (10g/day even though rated @ 50gpd), then the output decreased to practically nothing. I figured I had gotten a bad system (it was really cheap), so I got a new one. The exact same thing happened with the second system. I'll spare you the details on how I ended up with the third one.
<Mmm... what is the supply side water pressure here? Many households have only about 50 psi... This low pressure translates to much less water being pushed through the RO membranes>
Things I know for sure:
1. The KH of my source water is about 25. That's the only water quality test I've done, but I think the water here (city water) is remarkably poor.
<Mmm, do see your water bill/s... contact the agency supplying, ask them to forward you an analysis of the water>
2. If I replace the RO membranes in any of the systems, I get increased flow for a few days (up to 5-10gpd though it should be 50+ according to the systems I have) then back to 1-2gpd.
<Well... there are a few other "large possibilities" here that might account for the low and diminishing RO water processing. First, do you have someone who can come and "look over" your install? Am wondering if the cartridges are arranged in order... Next, are you collecting the produced water in a non-pressurized container? I.e., just letting it flow into a car-boy, trash can or such, not a "tank" with a pressurized counter. The back pressure greatly restricts production>
3. I've tried tapping into my source water in two different ways: from a faucet and from the spigot that my washing machine uses. I'm assuming that the spigot has higher water pressure and that its water is colder, but I haven't tested this. Regardless, I don't get good flow from either source.
<Mmm, have someone w/ plumbing experience check your houses pressure (reducing valve) regulator (often inside the garage)... and if your "plumbing will take it" increase the pressure to 80-85 psi (the max. permitted in many places)>
4. I live in north Illinois. It's cold as hell here! Perhaps my source water is too cold for a RO membrane to process efficiently. I tried running a 20'0" hose from my source water thru my dump (with a couple extra heaters) to see if I could warm the source water that way. If there has been any improvement, it's negligible.
<Water temp. (unless frozen!) has little to do with this>
5. Using both hot and cold water from the faucet really isn't an option, because my hot water heater is already too small for the house and without the added load of the RO/DI system I barely have enough hot water to bathe.
<Mmm, while that plumber is out measuring your static water pressure, have them check your distal outlets... you may have an issue with the lines...>
Help! What should I do? My best idea is to try a Kold Ster-il system?
<This is a worthy tool, product of Poly-Bio-Marine, but...>
But I'm hesitant to buy one without your ok because I really don't want to own four water purification systems and still have no water. :(
Looking forward to hearing your thoughts. Thanks in advance.
<Let's chat over, investigate the possibilities mentioned above. Bob Fenner>
Re: More...re: Water Filtration 3/23/11

Thanks, Bob, for the recommendation. The plumber is my next door neighbor so I'll call him to come take a look.
<Great! That's handy>
And yes, I have been collecting my water into a non-pressurized container. Is this the kind of pressurized container that I should be looking into?
<Actually, not. You do NOT want a pressurized container... whatever non-pressurized one you're using is fine>
If so, I'll get one after the plumber comes if things still aren't going well.
Thanks much,
<Thank you, BobF>

62 TDS after going through R/O system. Why? 11/12/10
I've been battling Cyano since April. I've been looking at everything in my setup to determine the source of the problem. I decided to make sure my R/O system was working properly by buying a TDS meter. I received it last night and tested my water. Here are the results:
Faucet: 152 TDS
Water after going through R/O system: 62 TDS
As a comparison, I tested our Ice Mountain spring water we drink and got 1 TDS.
I also made sure the membrane was seated properly today. It was, and produced 62 TDS water after I reseated it.
<Not uncommon.>
I have the Coralife 24gpd three stage system. I replaced the membrane 1 year ago and have NEVER run hot water through the membrane by mistake. I flush the membrane monthly and change the prefilter and carbon every six months. I have had the unit itself for about three and half years.
Why do you think my TDS is high?
<This is not an unheard of level after going through an RO unit. 62 ppm could be anything or a combination of that the membrane did not remove and in most cases is not a concerning level. Now if you were to live right across the street from a dairy with holding ponds while pulling water from a well, it could be near pure nitrate.>
What should I do to fix my problem and get the TDS close to zero?
<Simply add a DI stage to it. This will get near any level to zero. Your TDS out of the RO will determine how long the DI lasts. I have a similar system to yours. I pull 40 out of the RO, 0-1 out of the DI end. The DI gets replaced twice a year at $10 a pop.>
<Welcome, Scott V.>
Re: 62 TDS after going through R/O system. Why? 11/16/10

Thanks, Scott V.
<Ah, my pleasure.>
Is my membrane working correctly?
<It sounds like it.>
I thought it was supposed to remove 98% of TDS. Based on my source water of 152 TDS, shouldn't it get it down to around 3 TDS if it's working correctly? Do you think I need a new membrane?
<Hmm, your TDS is on the high side, but not unheard of. 62 sounds like a big number, but for the most is not. Heck, if I had tapwater with a TDS of 152 I would just use that myself if the water tested okay for nitrate and the such!>
I'm considering just selling my unit and buying a 75 gpd 5 stage RO/DI unit from Bulk Reef Supply that includes the pressure gauge and dual TDS meter.
What do you think?
<Great stuff. Andrew has some great deals on his site for these units (and most all he sells). For the price you will get the DI that will bring your TDS down to zip for not much more cash than replacing your membrane and other stages!>
<Welcome, have a good one.>
Re: 62 TDS after going through R/O system. Why? 12/6/10

Thanks for your help, Scott. I bought the BRS RO/DI system and I'm very happy with it so far. Finally 0 TDS water!
Great to hear, have a good holiday season!
Scott V.

TDS values 11/11/10
Hello out there in cyberspace! Hope it's not too cold J
<Not here!>
I use an RO/DI system like many reef keepers. And like others, I have a TDS meter to monitor my makeup water. The meter also helps me determine when to change my cartridges and DI resin. What I don't really know is what TDS reading should signal a change. For example, is a reading of 1 significant for RO/DI water?
<1 is nothing, not to worry about.>
Frankly, I've never seen a chart or definitive recommendation. I have, however, heard and read many opinions on the subject. I'd like yours, please.
<I know one of the things you read about quite a bit in the forums is TDS accuracy. Who really cares? It is just gives you an idea of when your DI resin needs replacing. What will happen as your resin gets used up you will see your TDS all of a sudden start climbing fairly quickly. Going from 1 to say 30 in a period of a few days. Just watch for the climb and you will know it is time.>
<Welcome, Scott V.>
Re: TDS values 11/11/10

Thank you Scott -- this is the most helpful explanation I've read yet. One fellow reef keeper seems to be an alarmist. He claims if my reading is "1" I need to immediately change out my DI resin.
<No way! Even the best of TDS meters have a error rate of 1 PPM!>
I've changed my cartridges -- but not my resin -- and I've had the system for about 2 years. My reading is still "1" -- and it could be that my source water is pretty clean to start with. I guess I could measure it too -- but if my RO/DI water is 1-ish -- I feel safe based on your comments.
<Well, inaccuracy is what some claim. Unless your TDS is completely worthless (I have heard nor used non that are), you will see a marked increase.>
Thanks again,
<Welcome, Scott V.>

RO/DI Problem Making Me Nuts!/Jack Daniels, If You Please 11/03/09
Hello Crew!
<Hello John>
I have a quick question about my RO/DI unit. I used to run a 60 GPD RO/DI unit that ran 24/7 and filled 50 gallon water tanks. I recently upgraded to a 200 GPD unit (1 prefilter, 1 carbon block, 2 "piggy-backed" RO membranes, and 1 DI). The pressure gauge read 78 PSI, (the old 60 GPD unit's pressure read about 60 - 65 PSI), but the new unit worked terribly. After 1 week of running it 24/7 I contacted the manufacturer who was only about 1 hour away.
I brought it back and had them tear it down and rebuild it. I even had them add a 3rd 100-GPD RO to it, making it a 300 GPD unit.
I was very excited, and rushed home to try it again. It still sucks. The pressure still reads 78 PSI but the unit only makes about 50 gallons per night/ (appx 12 hour period). It should be making 150! I have even gone so far as to re-plumb it so that it has 1 prefilter, 2 carbon blocks, 3 RO membranes and 3 DI canisters, (each RO goes to it's own DI canister and each DI canister has its own "product water" line). I was hoping that this would alleviate any "bottle necking" (the three RO membranes used to have a 4-way intersect that fed a single DI canister). All 3 waste water lines still intersect at a 4-way and have one 1/4" waste water line. Unfortunately, this did nothing to help, (but it looks cool, ha ha).
Should I try using 3 separate waste water lines, (with no 4-way intersect)?
Do you think that the water pressure is too low for a 300 GPD unit, (the water comes from a garden hose)?
Is 78 PSI is too much pressure, (maybe causing an issue)?
<The problem lies with using multiple membranes which creates a much higher pressure requirement to achieve efficiency. To improve your situation you would need to install an RO water pump in-line with your faucet/hose to increase the water pressure to the R/O. These units will generally increase
water pressure up to 50psi. See here.
http://www.drsfostersmith.com/product/prod_display.cfm?c=3578+4395+4473&pcat id=4473
Keep in mind that these pumps can only be used with a maximum of two membranes. For your desires, you would do best by using two dual membrane 150GPD units with each having one prefilter and one carbon block and it's own R/O pump.
Adding additional prefilters and carbon blocks just adds to the pressure problem. You may want to read here and related FAQ's before making another move.
Thanks for all your help!
<You're welcome. James (Salty Dog)>
Re RO/DI Problem Making Me Nuts!/Jack Daniels, If You Please 11/03/09
I'd like to ad this to my reply.
Cold inlet water temperatures will proportionately have a profound effect on the efficiency of the unit.
<Will append! BobF>

Re: RO/DI Problem Making Me Nuts!/Jack Daniels, If You Please 11/03/09
Hmmm, so 300 GPD RO/DI units don't really work unless the user has a 200 PSI garden spigot? Perfect! I'm glad I made the investment! Is there anything that I can do without having to ditch my $400 unit?
<No, not saying they do not work, at least not at rated production, but when you put three RO units together you are effectively reducing the pressure to all of the units making them less efficient. When companies rate the GPD of their systems, they are likely basing it on a water pressure of at least 55psi and a water temperature 70 degrees or above. Cold water temperatures can drastically reduce the output of a RO unit. Have you asked the manufacturer as to your concerns stated in this thread? If not, I would be directing this at them as to why you are not getting the advertised water production from their unit.
It will be interesting to see their response. I had a 50GPD RO unit and the only time I was able to get close
to the rated production was in the summer months with a new membrane, in winter about half the amount. This was based on my average water pressure of 55psi.
When I inquired about this, I was told my water pressure was too low to produce the rated amount.
James (Salty Dog)>

RO filter question 4/15/09
I bought a 6-stage 110 gal/day Reverse Osmosis Water System + 2DI filters for my reef tank a few months ago and I'm wondering if I'm doing something wrong. The RO filter is hooked up to the cold supply line under the sink with a ball valve and I usually place the filter on the counter with a line running to it from the supply, place the waste line into the sink and the output into a couple of 5 gallon jugs. The filter system has a pressure gauge on it also. The problems I seem to be having are:
1) the water coming out of the filter is really slow. When I turn the water on the pressure gauge usually reads about 50 psi (just FYI, the water supply to my house has always seemed slower than normal),
<50 psi is perfectly functional for one of these units, though the 110 rating may very well be for a higher water pressure.>
and the water comes out of the filter into the jugs at a little more than a trickle and it takes more than a few hours to fill 1 5-gallon jug.
<How long exactly? Even for one of these "big" units a few hours for 5 gallons is not unheard of.>
2) and what seems to be more alarming, is the RO system doesn't seem to be taking the phosphate out of the water. I tested the water in my tank and the phosphate seemed a little high, afterwards I also tested the water in my jugs from the RO filter which came out to be around 0.25 - 0.5. I decided to test my tap water directly and got the same exact result as the RO water, which doesn't seem right.
<With the two DI filters alone on there you should be getting 0 phosphate.....at the very least a difference in the reading after filtration. Are these DI canisters new? This can likely be attributed to the test kit, I would haul a bit of water down to the LFS and have them test for phosphate with a different kit to be sure.>
Is there something I'm doing wrong?
<On the surface everything actually sounds fine. The output on these is highly dependant on input pressure. 50 is not bad, but it is not going to give you the maximum out of the unit. If you are getting 5 gallons every 2
hours that sounds reasonable. Now if it is taking 4 that is a different story!>
<Welcome, Scott V.>

Kent marine maxima 24 GPD RO/DI Systems, before or after softener? 3/5/2009 Hello, <Hi Willian> I have a quick question for you. I just received my Maxima RO/ DI and had an installation question. Should I hook it up before or after my house water softener? <I would put it after your softener.> Thank you, <You're Welcome> William <Mike>

Help please!! RO Unit 1/1/09 Hi all and Happy New Year! I have spent the last 2 months working in the Middle East. I have at the same time split from my partner and now find myself with the challenge of looking after my 200gl tank and all that goes with it alone. My most burning question at the moment is - how do I get my RO machine started to build up my reserves of water for top up. I have a RO-Man 100, which is plumbed into a house water cold feed via a T bar tap. I have turned the T bar on and I think I have the unit tap in the right direction too, but nothing is happening! What am I doing wrong? Kindest regards Sarah <It is really hard to say from here. Are you getting any water at all through the unit, anything coming out the waste line? Do you have a diagram/manual you can reference? Scott V.>

Re: Help please!! RO Unit 1/1/09 Hi. <Sarah.> No nothing coming out at all and no, I have know diagram or manual to use as reference. I will go and buy some fresh water tomorrow and get the local 'fishman' to come around and help me work out the system. <A good route to go if you know somebody knowledgeable. Typically you get wastewater even if things are plumbed wrong. If you are getting nothing it is likely you are not getting water to the unit at all or the waste line is shutoff/obstructed. > Thank you for your quick response. Sarah <Welcome, Scott V.>

Kent Maxima Hi-S RODI Unit, repair 11/26/08 Hi, I need help. I purchased a Kent Maxima Hi-S RODI unit from Craigslist. I don't know how old the unit is but it looks like it can't be more than a year or two old. When I bought it, it was new in the box. Never been open. It was purchased from Marine Depot and given to the seller as a present. The seller is moving from SF to Minnesota so can't take it with him. Thus, this is why I have the unit. The unit is a 60 GPD. <Okay.> I connected the Hi-S membrane filter into the housing with the o-rings down into the housing. The space from the top of the filter to the housing is 1/2 exactly. I measured it with a tape measure. When I connect the line to the outside hose (garden spigot) the water moves quickly from the first canister to the second. Then the water moves to the Hi-S filter. From there the water moves into the third canister at the rate of 1 drop every 3 seconds. I ran the unit for 2 hours producing 9 gallons of waste water and 1/4cup of RODI water. <Not good.> I then took all the hoses apart to make sure the lines were not plugged up and blew through them with my mouth to make sure I could feel air. I took the filter out of the Hi-S housing and reseated the filter to make sure I had it in all the way. Then reconnected everything and reattached the fitting to the garden spigot. Still the same results. Can someone please help me. The third canister is only 1/2 full after 9 gallons of waste water and 2 hours running time. From a friend of mine, he says I should get at least 2 gallons of RODI water out of 9 gallons of waste. <You should.> My unit does not have the pressure gage which tells me how much water pressure my house puts out. Do I need one of these? <No.> Or is there another way to tell how much water pressure you are getting from the outside of your house? <Most city water pressure will give you enough pressure for the filter to function.> Also, do I need to replace any of the filters. However, remember the filters are new (never been used) and they were still in the plastic! <No, they sound fine.> I also am wondering can I take the unit someplace to have someone look at it or can I send it to someone for service? <Well, it is fairly straightforward. From your symptoms it sounds like either the flow restrictor (goes into the waste line coming off the membrane housing) is backwards/not there or there is a bypass on the waste line for flushing the membrane that is on. It would simply be a valve on the line, close it. For the flow restrictor, look here for an idea of what I am talking about: http://www.reefgeek.com/care_&_maintenance/Water_Purifiers/Replacement_Filte rs/RO_Flow_Restrictor_-_60!75_gpd_(blue)_by_Farris_Enterprises It just slides inside the waste line.> Please let me know what I should do. Thanks! Stephanie (SF Bay area) <Welcome, Scott V., Fresno, Ca.>

RO Filter Troubles 9/13/08 Hi Crew, <Christopher.> I'm not sure how to search this, and thus can't find an answer. My local fish guy can't give me a straight answer either, so I'm hoping maybe you can :) <Certainly.> I have an under the counter RO water filtration unit. It has a 5 micron sediment filter, 2 carbon filters, the membrane, and finally another carbon filter. <I would not personally run your tank water (or drinking water) through the last filter. These really do nothing if the RO is working correctly, sold as a taste filter. If the water is RO pure coming out, why do you need to modify the taste?> It has a 5 gallon storage tank. I recently discovered the water flow valve (not sure what it's actually called), which is on the waste line that connects to the drain, was installed backwards. <The flow restrictor?> I corrected that. At the same time I replaced the membrane because my fish guy who sold it to me said because of the smell of the water the membrane must be shot. <Hmmm, I would test the water after back-flushing the membrane first, invest in a TDS meter.> So I replaced the membrane, and did the flushing instructions that came with it (filling the unit and emptying 3 times). The water tastes great now, but, I noticed my sediment filter which was white 3 days ago, is now bright orange/brown. I've never seen it change color this quickly! The water tastes fine, but I'm worried either I replaced the membrane with the wrong one (they looked identical) or by reversing that valve on the waste line I've caused something. <Both are possible, a few signs to look at. First, is your waste output higher now? If so the membrane may be wrong (leaking past inside the housing, doubtful) or the flow restrictor may have indeed been correct in the first place. Either scenario would flow much more water through the sediment filter (nonstop), filtering more water, which may lead to the swift color change. The other thing to consider is how fast the RO water is produced. You may not get much RO water produced with the flow restrictor installed incorrectly, was it producing water faster before or now?> OR finally is my water is just coincidentally high in algae at this exact time. <Possible, such extreme coincidences do happen but rarely.> I live in the city and we get a lot of algae in the water during summer time. <The orange color in the sediment filter suggest rust rather than algae.> But again, I've never see it change this fast. <I would take this system down and look at the manufactures diagram on how it all goes together, make sure the two mesh. At first glance without knowing the answers to the questions above it does sound like the flow restrictor may have been correctly placed to begin with. If the assembly is exactly that of the diagram, I do suggest contacting them regarding this.> I figure I've gone through about 20-30 gallons on these new filters, which is very little compared to what I normally do on a filter. <Not much for the sediment filter to handle, if something is installed wrong or the incorrect type this unit may be running water through the sediment portion 24/7. Do consider investing in a cheap TDS meter, this can tell you much about what is going on with this filter/membrane over time.> Thanks for listening and hope you can help !! Christopher <Welcome, Scott V.>

Re: RO Filter Troubles 9/13/08 Thanks Scott ! After a lot of reading of what each component does, I think you are right and the flow restrictor was right in the first place, however the sticker says otherwise, but am going to change it back and see what happens. <Yes, do. This really does sound like the culprit, all things considered.> Thank you ! <Welcome, have fun, Scott V.>

Reverse Osmosis Filters Cheaper Than Realized? 08/07/08 Unfortunately, I did not research prior to buying a used Kent Marine 24 gallon per day unit for the price of $125. <<Mmm, yes a bit of looking around could have found you a new 75gpd RO/DI unit for about $10 more>> I need to replace the membrane, and all three filters of this unit. <<Easy enough to do these units are all pretty much standard and the membranes/other components are easily interchangeable>> I can upgrade the unit to produce 50 gallons per day, but the cost will be $183 to do this. Add this to the $125 cost of the filter, and I cannot help but wonder if I should just purchase a new SpectraPure reverse osmosis filter that will produce 100 gallons per day, at $199 plus shipping. <<SpectraPure is a good product (is what I have), but you can use your current housings and upgrade your membrane and flow restrictor here (http://www.thefilterguys.biz/ro_membranes.htm) for a mere $56plus a little more to replace the other components>> Unfortunately, I already spent $125 for the unit, so an additional $183 to replace the filters and upgrade the capacity to (still) only 50 gallons per day will mean I am spending almost $300 for the unit! <<Do look in to the link I have provided>> I guess my question is: is the Kent Marine filter such a superior product that it warrants such a price ($260 new) for a filter that only produces 24 gallon per day? <<This is for an RO/DI unit? Hardly Most of these units and components are made by a few manufacturers (e.g. DOW) and then distributed and remarketed/relabeled for selling by the different vendors. Have a look around on line at the independent vendors (even those not from the hobby interest)this technology is not/should not be that expensive to utilize>> Regards, Jeff Castaldo <<And to you. Eric Russell>>

Re: Reverse Osmosis Filters Cheaper Than Realized? - 08/08/08 Thanks so much for your quick reply. <<Quite welcome>> I went there, and these guys are even cheaper than waterfiltersonline.com! <<Indeed TheFilterGuys.biz is a great place to get your RO/DI systems and replacement components. I go to them for my own needs service is excellent>> I am new to your website, but I can see it right now that I am going to enjoy it immensely. <<Ah, welcome then>> Regards, Jeff <<Cheers, EricR>>

TDS Readings Leaching Storage Container 07/16/08 Greetings All, <<Hello>> THANKS in advance for a wonderful web site, <<Quite welcome>> unfortunately I couldn't find an answer to my question/situation so I must pick a few brain cells. <<Not too many I hope, I only have a few left and many of those have been allocated to destruction via alcohol consumption [grin] >> I have a 7 stage RO/DI set up in the basement; the water drains in to 2 55-gallon blue barrels that are food grade--they had tomatoes in them previously <<Okay>> --the 2 barrels are connected via 1-inch PVC at the bottom so that as one fills, it fills the other. <<Understood>> As needed, I pump water into a 3rd 55-gallon barrel for saltwater changes one week prior to its use. <<Sounds good>> My TDS readings are at 001 out of the unit, and within the last 3-4 weeks the water in the barrels has started reading anywhere from 35 to 80ppm. ANY IDEAS????? <<Ill assume you are not adding buffers to these containers (would expect much higher TDS readings if so), so this is likely the result of something leaching from the containers themselves. This may be something that was previously absorbed from the tomatoes, or something from the barrels makeup. You say these containers are food grade but that doesn't mean they don't/wont leach chemicals it just means that whatever they leach should be safe for human consumption. Water is a universal solvent some leaching is not unexpected, even were these new containers, and I think it likely they are indeed safe for your intended purpose here. You could take a sample for testing (perhaps at a College/University laboratory) if overly concerned, but if your tank inhabitants are not displaying any unexplained issues of late or nuisance alga hasn't sprung up unexpectedly, I would be inclined to ignore these readings and continue as you have been doing. Regards, EricR>>

Re: TDS Readings Leaching Storage Container 07/17/08 Eric, <<Bill>> THANKS for the speedy reply. <<Quite welcome>> My fish and corals all appear to be doing fine. Polyp extension is very good, and colors are unchanged. <<Very good>> I have noticed however, a red slimy substance that has started to cover a portion of the algae and rock in my 'fuge, but not in my tank. <<Cyanobacteria and not uncommon in these typically low-flow environments>> I do remove this red slime by simply using a 'fish net'. <<Good>> The only thing in my two 'storage' barrels is the RO/DI water, no buffers or any other additives. <<Okay>> There is an airline with a 'T' on the end in each barrel for circulation, and a heater is used in the winter. Due to the increased TDS readings in the stored make up water, I drained both barrels last Sunday, scrubbed the two containers with a VERY mild water/vinegar solution and thoroughly rinsed then dried with paper towels as I did prior to their initial use, and started the refill. <<All good, though this may only have a short-term effect time will tell>> ALL filters/media in the system with the exception of the 100 GPD membrane, (it was replaced in March), were changed on Saturday, and allowed to run for 3 hours before collection. I am seeing a definite increase in green algae on my substrate and glass, but I attribute this to new 20 k HQI bulbs put in last weekend (They replaced 10 k bulbs). I have cut their 'on time' down to just a little over 8 hours from 10. <<Lighting is but a part of the nuisance alga equation and I am not a fan of reducing the photoperiod to battle such as I feel this does more harm to your desirous photosynthetic organisms than to the alga. I cant say whether the appearance of the green algae (and/or the Cyanobacteria) is attributable to your water storage barrels but I once had a previously used Polyethylene barrel for storage of my RO/DI makeup water that I attributed to nuisance alga growth. I replaced the barrel with a new one, and the nuisance alga disappeared within weeks. Coincidence? Maybe but still something to consider>> So as long as my readings straight out of the RO/DI unit continue to read 001 I'm good to go--OK. <<Too nebulous Let your tank/common sense be your guide here>> At what point/level should I be concerned with the stored water readings, if at all?? Bill <<That's a tough one Bill not knowing what element/substance is registering on the meter to begin with. If the algae you mention doesn't become problematic and the fish and coral stay healthy then no problem. If things start to go downhill then you need to try to determine the reason and the source with contamination from the storage barrels being but one of the options. Regards, EricR>>

R2: TDS Readings-Leaching Storage Container - 07/19/08 Eric <<Hiya Bill>> Again, THANKS for your response. <<A pleasure>> I went by the facility that I have been purchasing my filters etc. from on my way home form work this morning--his price is way cheaper than any LFS in my area <<Give these guys a browse: http://www.thefilterguys.biz/ >> it is a home Water purification store, and as we were discussing the recent events of my water situation, we came to the conclusion that the GPD membrane/filter is bad. <<Mmm, maybe so but your DI resin cartridge would be (is!) cleaning up any leakage of ions through the membrane. A bad membrane should really only result in the faster exhaustion of the resin>> At his suggestion ran a 'test' of it the night before, and after 15 minutes I had collected less that 1 gallon of RO water, so I ordered a new membrane. <<I don't know that this really proves anything here, Bill. I get the logic that a 100gpd membrane should process at least 4-gallons per hour (e.g. 1-gallon every 15-minutes), but these ratings, while likely in the ball-park, are subjective to a bit of marketing hype/over evaluation just like anything else (e.g. the skimmer that's good for any tank from 25 to 300 gallons). Water pressure, level of impurities, and very importantly water temperature (the colder the source/ground water the more waste-water produced per gallon of filtered water and thus a slower filter rate) also affects the performance of these membranes. My own 100gpd unit runs fastest at this time of year here in the South, and my source water starts off with an already low TDS of about 80ppm on average but I don't think that it is producing a gallon of purified water every 15-minutesthough I have not bothered to measure this. And a suggestion if you don't have one already, the small amount of money to add a membrane flush-kit to your filter setup would be well spent>> It will be in on Monday. He also stated that these membranes need to be stored in a refrigerator prior to their use, as they will deteriorate just sitting on a shelf, and it is quite possible that I received a bad one to start with, and suggested I have it replaced under warranty. <<Hmm cant say I agree with all this>> Although this sounds good in theory, I'm a little leery of receiving another bad one, and going through this scenario again. I also discovered that he has 55 gallon barrels in stock, the price is higher than I paid for my current ones, but they are brand new food grade barrels, and have never been used. <<I ordered mine form USPlastics.com>> He also showed me some water storage barrels that he has leftover from the Y2K scare that are also brand new/food grade and are plumbed for water delivery. <<Ah yes, mine came with spouts as well very handy>> They come in 250 and 125 gallon size. The 125 is not much more in price than 2 55 gallon barrels and has a smaller footprint that 2 55's---SO in light of recent events, and not wanting to jeopardize my corals, I'm going to pick up one of these tomorrow--Friday-- and start anew. <<And will hopefully eliminate this variable/concern re your water quality and the used barrels>> I've also got a new TDS meter on the way as well. We'll see. <<Indeed>> Hopeful Bill <<Do keep me posted mate. Good luck! Eric Russell>>

R3: TDS Readings-Leaching Storage Container - 07/23/08 Greetings Eric <<Howdy Bill>> OK, first insert "Stretch's line from 'Animal house' here-- "... What are you some kinda moeron?..."(and yes I know moron is spelled wrong) <<Hee-hee! What did you do know?>> I realized that I was using my TDS meter wrong on my readings of water entering my first container. I was just holding it under the water as it entered/filled the barrel. <<Ah>> Hey, I got the reading I wanted <<Indeed [grin]>> I washed/rinsed out both collection barrels, dried them with paper towels, and let them air out. Back-flushed the system, installed the new membrane, found out that there was no restrictor anywhere in my system, <<The missing restrictor is the reason your filtered affluent rate was so slow (low pressure against the membrane), and probably not the fault of a bad membrane>> good thing Dan (owner of water supply store) got one for me with the new membrane, flushed the membrane for an hour into a 5 gallon bucket (collected 1 gallon in 15 minutes) and started refilling the barrels. Using a glass jar to collect water going into the barrel my TDS is 002, and the water in the barrel reads 002, after 24 hours of collection. <<Yay!>> Therefore, I have concluded that 'IF' I had been using the meter correctly I would have seen that my collection water was the same TDS as water entering the barrels. <<Very possibly so although not at optimum efficiency re the missing flow restrictor>> I'm still unsure as to why my membrane went 'bad' so soon, I replaced it in March--4 months ago--at the same time I replaced all the other filters. <<Mmm, give the old membrane a try with the new restrictor in place may not be bad after all>> Anyway, it's the weekend to do one of the twice monthly water changes, but I'm thinking maybe I'll do one every weekend for a couple more weeks. <<Up to you mate>> THANKS again for being here for all of us, I know I appreciate it. <<Is my pleasure to share>> Bill Fletcher in Kansas City, MO <<Eric Russell in hot and muggy Columbia, SC>>

RO Filter Hookup 6/15/08 Hey Scott, long time no see. Hope all is good. <Hello John, it is!> I wanted to give you an up date and had a question for you. Well, the tank has cycled. I have purple coralline algae starting to spread on rock. <Great!> I have Chaetomorpha algae in refugium. ALL readings are good. My question is I am now planning on purchasing a ro/di unit pref (Barracuda) is there a model you suggest 50/100 gallons per day. <The 50 will give you all the water you will need. The 100 will likely cost little more, but the membrane for the 50 will likely be significantly cheaper to replace down the road.> I want to also use a Tunze auto top off with this. <A good, reliable choice.> I am going to tap into the cold water pipe in the basement just after the outside valve and the main turn off for the outside water valve. I guess there's a drain involved so I was going to run a piece of PVC approx 1" or 3/4" through wall outside. I am going to put the drain line from the RO unit into this drain pipe. How does this sound so far? <If you do not have a drain nearby to use, all you will need is to run a length of ¼ o.d. poly tubing (the type for icemakers; it will fit directly into the filters output/waste water fitting) outside. No need for anything larger.> My other question is do I put the output supply to a holding tank with a float valve in the sump. <Yes, put the water into a holding tank (new, clean trashcans work well). A float valve (in the holding tank) combined with a shutoff on the filter will allow you to always have a full reservoir without having to constantly turn things on and off.> What size holding tank? <From a few gallons for water changes up to whatever you have room for. Ideally, you should have enough water for a full water change should a catastrophic emergency arise. With large tanks it is more practical to have enough water to fill the quarantine tank (or use the holding tank itself) in such an event. I should also mention it is a good idea to have a separate tank for the pure RO water and your saltwater mixing tank. This will allow you pure top off water and not clog the float valve with any precipitation that may accumulate from mixing salt.> I think Barracuda has an optional float valve, should I use this unit? <It has an optional shutoff valve that works on diaphragm pressure differential. When the output is shutoff it shuts off the input water to the filter. This in turn keeps the wastewater from continuing to flow.> What parts do I need to make this work? <The filter, shut off and a float valve, I use the all plastic Kent's. The Tunze will need a reservoir to pump from into the tank. A 5 gal bucket works well. There is a way to directly plumb your RO safely into the Tunze unit if you are at all handy with a bit of simple electrical work, eliminating the need to haul top off water. Let me know if this interests you.> Thanks again for your help. <Very welcome, always a pleasure.> Happy fathers day! John <The best to you too, Scott V.>

Re: RO Filter Hookup 6/16/08 Hey Scott thanks again. <My pleasure.> Yes I would like to plumb the R/O unit directly to the Tunze. Do you know of any on line links of how to set this up? <None that I am aware of I just created one: http://reefercentral.com/tunzeato.html I have been telling myself I would do this for a while, you drove me to it!! I will have to include some pictures in the future, but this does give you the low down on how to do this. You will have to excuse the name of the site, it is a temporary site while we build our new site, kind of a play on words between my partner and I. Don't believe that we don't spend quite a bit of time answering queries!> I am pretty handy. This would take care of the auto top off. What about water changes? Can I tee off the supply one to the Tunze unit then one to the other holding tank for salt mixed water? <If you have the tank above the tank (to gravity feed) or have a pump to drive through the line. The only other problem is the units time out (discussed it the link above), it may not allow enough volume through for a water change.> Sorry for the stupid questions. "I 'am getting deep into this" <Heee, aren't we all! Enjoy, have fun, Scott V.>

RO/DI Filter Storage 2/23/08 I looked through the FAQs and didn't come across a similar question. <OK> I have a 4-stage 50GPD RO/DI unit that I use to make batches of water which I store for top-off and water changes. It is only necessary to make water approximately 5 times per year as I have a small system. As such, I tear down the RO/DI unit between uses and do not leave the filters in the RO/DI unit. It is my understanding that the RO membrane can be kept in a zip-lock bag with a couple tablespoons of RO water in the refrigerator and will be okay as long as it does not freeze. <Yes, keep it moist. I would put the Ziploc inside a paper bag or other container to keep out light as well.> My question regards the other filters. I assume that the micron pre-filter and carbon filter can be left to dry out without harm between uses? <Not a problem.> What about the DI filter? Can it be left to dry out between uses, or should it be stored it in a different manner? Your advice would be greatly appreciated. <I recommend keeping the DI cartridge in the same manner as the RO membrane. Keep it moist and dark. Welcome, Scott V.>

RO/DI Question 1/26/08 Dear Crew, Hope you're having a good weekend. <Hello Andy, very good here.> I have a question that I think has an obvious answer, but I'd rather be safe than sorry. I purchased a 6 stage RO/DI unit about 8 months ago. <Nice.> The DI cartridge is clear with two blue end caps, and it has color-changing resin. The unit was pre-assembled. The instructions that came with the unit were not that great. I attached a TDS meter at the same time I installed the unit, which showed that the unit was definitely working (117 in to 0 out). <Excellent.> My question arose when I decided to replace the DI canister. When I was getting ready to unhook it, I noticed that the canister's plastic housing has what I believe to be a flow direction arrow. This arrow was pointing in the direction in which the water was coming into the canister--opposite the direction that common sense tells me it should be pointing; rather, common sense tells me that the butt of the arrow should be pointing towards the end from which the water enters the canister, and the head of the arrow should be pointing in the direction in which the water flows out of the canister. <I agree.> For the heck of it, I flipped the canister. When I ran water through it, I noticed that the purified water had a lot of bubbles in it--it was not a steady stream as was the case when the arrow was pointing the other way. <Likely purging air, it can take a while with the slow flow through these units.> My TDS meter again showed 0 coming out. Over time, the bubbles went away and now the water is a steady stream, although I think the water flow rate is a little less than it was when the canister was as originally positioned--I can't be sure of this, though. Would you please confirm that this arrow should, in fact, be pointing in the direction in which the water flows through the canister? <Yes it should, little actual difference in most of these units the way they are designed, both ends are usually the same.> From my TDS readings, it appears that the direction may not make any real difference, but I want to be sure. <It really should not, but if it has a flow arrow, you might as well follow it.> Thanks much! Andy <Welcome, Scott V.> Re: RO/DI Question 1/26/08 Thanks, Scott. The ends look the same so I figured it didn't really matter, but I wanted to be sure and couldn't find anything on the web. <Thank you for writing Andy, Scott V.>

Water Purification System1/16/07 I am looking for the hardware to re-hook up my Culligan system as all the hose connections now leak and some of the parts are missing. Specifically I am looking for the 1/4 inch hose, connectors and threaded nuts to hold them to the units. <Compression fittings.> I was able to find 1/4 inch hose, two and three way ball valves but the correct connectors which consist of 3-4 parts per connector are seemingly impossible to find. Do you guys know where I can find this stuff for sale? The normal places are just about helpless! Home Depot, Lowes, Orchard etc. I could call out a Culligan guy but you know the story that would follow that! I was able to find replacement filters online but it seems I am on my own for the hookups as they do not sell the pipe or accessories, they just sell replacement canisters and I need to re-connect to all the canister holders. My friend used to work for Culligan and even he is stumped as he has been out of the business for a few years. Any Ideas? Thanks, John Zunich <Check out Premiumaquatics.com for Jaco fittings. If they don't have what you want McMaster.com surely will, it just may take a little searching on their site. Hope this help out, Scott V.>

Re: Water Purification System - 1/17/08 Thanks so much. <Very welcome.> Just to put it out there..........A friend of mine wrote me a warning to say that reverse osmosis purified water should not repose in copper tubing as it leads to toxic levels. He is generally well read so be warned and thanks for the tips. john Zunich <Yes, I have read about this, though have no first hand experience. The theory is the water has a great carrying capacity for CO2, making it more acidic and corrosive. Will pass this along. Thanks, Scott V.>

Re: Water Purification System - 1/17/08 To support this my take on this after reading his dissertation, is that the removal of minerals is the real cause and effect of the aforementioned phenomenon. All the best, john Zunich <Yes, thanks for the info John, Scott V.> RO water still high in Nitrates 12/24/07 Hello WWM Crew, <David> I am having issues with my RO water. I recently ran a test kit on my established reef tank and the kit showed all was in normal parameters with the exception of my Alkalinity which was low and my nitrates that were high at around 15 - 20ppm. I then looked to my RO water. I am using a Kent Marine 60gpd Maxxima HI-S system. The nitrates were still showing high around 15- 20ppm almost the same as the reef tank. <Uhh... something amiss here> I keep my RO water in a covered 45 gallon rubber made trash can that is heated, aerated and running a circulation pump. <... Mmm, I would measure the water out of the device, and over days time in storage... either a membrane is shot, the rig is not plumbed correctly... or the container is imparting chemical change/s> This Kent RO system is only six months old. I went to my supply company and bought another membrane and still had the same results. <Well... I'd review the install instructions... something is awry> I finally bought a whole new 60gpd Maxxima RO/DI system again with the same issue. <!?> I then purchased three separate nitrate test kits... Red Sea, API and SeaChem. All three kits were basically showing the same high reading around 15 - 20ppm. I called Kent Marine support and they stated that the nitrate test kits can give a false positive reading and cannot be trusted. <... What? Not simply by testing... perhaps with the addition of some water conditioners/dechloraminators... Please write these folks and ask them to respond in writing... send their note along to me> They advised me that I should use a TDS kit measure more accurately. I find this hard to believe since I used the same test kits on my cousins RO system (Kent as well) and the nitrate test was almost zero with all three tests.(city water) Even if the test kits were off, I don't think it would be by 15ppm....do you?? <No... there should be zip, nada, none...> My water supply is from a well which then passes through a whole house sediment filter, then a water softener, then the RO system. The only other thing I could think of is that the well water nitrate supply is so astronomically high that it is still getting through the 4 stages of the RO system. <Not to be (too) alarmist here, but I would NOT drink, cook with... use such water for potable uses> The last time the well water was tested was a few years ago and the readings were at 23.5ppm at that time. My next plan of action is to have the well tested and if extremely high in Nitrate, connect to public water. <You are wise here> I will also run a TDS kit for arguments sake, but I think I don't think three test kits are that far off. Please let me know if you can think of anything else that I might be overlooking. Thanks! Dave <Either serially faulty filtration units... some consistent problem in the arrangement of set-up of same... or something very anomalous with "something" else here. I would try another brand of RO... have someone come over and look over your install. Bob Fenner>

R4: High pH And Hair Algae 12/14/07 And a cheery Hello to you and the entire Wet Web crew in this Holiday Season <<Greetings Kerstin!>> - it's hard to believe it's over halfway through Christmas...and nary a card is written (spending too much time with my fish, according to my husband!). <<Nevah!>> Just one more comment...I found the source of the phosphates and even silicates (she and I both have a lovely case of brown diatoms on our sand!). <<Ah good finding the problem is half the battle won>> Hopefully this helps others as well... Last year we installed a new RO/DI system...the Hi-S version from Kent Marine. As a note to other users as well - remember your filter change schedule! <<Hee-hee, indeed! Are not plug-in and forget units>> I forgot mine, and didn't taste a difference in the water, <<Mmm, not a reliable gauge as you have learned. Better to use a TDS meter or at the least, a routine exchange schedule>> and so all of a sudden started having the diatoms on the sand. All my other parameters tested normal (Nitrate, Ammonia, Nitrite all 0, pH 8.2, Alk. around 7.9-8 dKH, calcium ~460) <<I wouldn't want this to go any/much higher is good your Alkalinity is at the bottom of the scale re>> ...so I thought I would finally put in a Poly-Filter pad to see if it helps <<An excellent product>> ...and it immediately started to turn light brown! At this point I researched the filter schedules, and, lo and behold, due to my own forgetfulness, found out that I was being mean to my tank by not doing a filter change. <<[grin]>> I should be getting new filters today, and will start doing regular twice-weekly 5-gallon water changes to my 92-gallon; <<10-gallons weekly will be fine and less of a disruption/irritation to your tank inhabitants. Do be sure to mix your saltwater up ahead of time and aerate it/give it some time to mature before use (minimum 24hrs is okay72hrs or more is better). Freshly mixed seawater is caustic to marine life and the chemical processes are still active for a while after mixing/dissolving thus the need for some maturation>> I am hoping that will reduce/eradicate the diatoms. My friend will also get fresh water to continue doing her water changes (and luckily she's not mad at me for also "giving" her the brown diatoms). <<Oops>> Her tank has radically improved since we started working with it, <<Excellent am sure she much appreciates your assistance here>> and now she is working on determining what fish she would like. Quick comment about trying to catch my 6-line wrasse...I haven't bought a fish trap, but have tried several homemade models. I think my fish thought that was the funniest thing I could do - completely ignored all of them (only used one at a time, but changed sizes and food types over the course of several weeks). <<Mmm, yes I have had similar experience with the traps. Seems they are best at catching only those fish you do not wish to capture>> However, it did calm down his "dominancy" over the Purple Tang, so they get along well now...the wrasse has even stopped harassing the Yellow Watchman Goby (at least when I am looking). <<The intrusions have likely upset this fishs routine enough/given it other things to focus on for the moment. As the tang grows/matures I would expect the wrasse to become less of a problem anyway the goby may be another matter>> And my dog was amazingly jealous over my sitting in front of my tank to catch the wrasse - every time I sat there, he HAD to be petted...too funny, as he is usually not so needy. <<Ha! Well between the tank and your dog, your husband must be feeling really left-out [grin]>> Anyway, I wanted to thank you again for all your help. <<Quite welcome>> I even found a link on your site to the Tunze forum, which let me fix my skimmer (9010, after 3 weeks, had still not foamed - simply needed to reconnect the air hose, which had loosened during shipping - the skimmer works beautifully now!). <<Excellent! Sometimes the simplest of things...>> Thank you as usual for the great site - I love all the info you and all your cohorts provide. Kerstin:-) <<Is our pleasure. EricR>>

Corallife pure-flo reverse osmosis unit Hi, <Karyn> A simple question, I hope: I have a Corallife pure-flo II RO unit and can't open the membrane housing. Has anyone else encountered this problem and is there a solution? Thanks -- Karyn Bradfield <Mmm, like all such "re-labeled" products, it's hard to tell whether the current model/s are sealed type TFC's or not... some are permanently encased (you toss them when they're past their usefulness), and some you can actually take apart and replace the membrane. I would contact Corallife/ESU re... And if they want what you consider "too much money", buy an OEM replacement from anywhere else that fits. Bob Fenner>

Re: Corallife pure-Flo reverse osmosis unit 11/13/07 Thanks. I finally got it open with a wrench and pure brute strength. <Thank you for this follow-up. Will post/share. BobF>

R/O Results 7/11/07 Dear Wet Web Media, <Hello> I have an R/O Unit by Coralife (24 gallons a day, 3 Stage) and I have a new membrane, micron filter and carbon filter for the unit. So here's my question. When the water comes out of the unit I am only getting the water down to 10ppm but the water going in is above 300ppm, is that real high for public water and if so can I add another unit with more stages? <Its pretty high, and 10 ppm is what would be expected with a 3 stage R/O starting out at 300ppm. You could get a 5 or more stage R/O DI unit and probably get 1 ppm or undetectable levels.> I was going to get something around seven stages because I want the water a pure as possible. Please write back and give me your thoughts thank you. Jeff <I would contact www.airwaterice.com and talk to the experts, see what they recommend. I have used their product for several years now and their customer service is top notch.> <Chris>

Severely frustrated... questionable LFS pre-made synthetic saltwater 7/4/07 I have tested the water (that I get from my LFS) that I use for water changes and got some results I don't know what to do with. The water is free from NH3 and NO2, but the NO3 reads about 5-10 ppm... and there is a modest coating of brown algae on the bottom of the container used to store the water (the water is a tad old, as well, maybe a month or so). <Mmmm...> I am not sure that that amount of NO3 would provoke the terrible algae growth in my tanks, but I guess it can't help. What do you suggest I do with these results? <Take them to the store, pose your concerns to the management> I plan on informing the store of this issue, procuring a new source of salt water (or still there, if it was just a faulty membrane) and raising calcium in my tanks to increase competition from corals and coralline algae. Any other advice or comments? <Yes... get/use your own water filtration device (likely a modest investment... Reverse Osmosis alone will very likely do...) and a couple of pieces of gear (a good trash can... my fave is the Rubbermaid "Brute" line, a cover, a pump, likely a heater, electrical multiple outlet cord to shut off when emptier...) and make your own water... IS much easier, cheaper in the not-so-long run... and far more satisfying to have control, quantities of water on hand for use of known make-up> PS I found this rather humorous---there is a stalk of xenia in my larger tank that was overgrown by hair algae, but now it is attached to the free end of the strands of hair algae, floating unperturbed in the current, with the "roots" left on the rock where it formerly was growing new xenia "buds." This stuff never does die! <Is tough indeed. Cheers, Bob Fenner>

Re: Severely frustrated... questionable LFS pre-made synthetic saltwater 7/7/07 Yet another delightful surprise...the RO water I was buying from the LFS to top off the tank had more NO3 in it than the salt water did! I think I will be taking your advice to make my own water... <Yes... as I suspected... Cheers, BobF>

My Liquid Rock Is Clogging My RO Membrane! 06/07/07 Dear Mr. Fenner, <<Tis EricR here to help today>> I previously sent an email requesting book titles to assist me in researching whether or not to set up a marine aquarium. These books (including yours) helped enormously. <<Ah, very good...Bob will be pleased>> I decided I did want to go forward with this, but have already run into a major stumbling block. <<Oh?>> My main ingredient (water) is going to be a problem I do not know how to overcome. <<Hmm...>> Source: Private Well. Tested and full of heavy metals, nitrates, iron, some phosphates etc. <<Yikes!>> Hardness is off the scale. Literally. You could kill someone if you threw this water at them! <<Ha! I think Bob feels much the same, re the hardness, about his water in San Diego. I guess Im quite fortunate to have a TDS of about 80 right from the tap>> Have already tried RO units for drinking water to alleviate having the haul water in. However the water is so bad, the membranes clog after maybe a dozen gallons. <<Mercy...truly liquid rock. But tell me, are you using sediment/carbon-block prefilters? I suspect you may be feeding the water directly to the membrane here. Adding a few sediment filters in-line ahead of the RO unit in decreasing order re the filters micron rating will greatly increase the output and life of the membrane. Additionally, adding a flush unit to allow flushing of the membrane after use will also help to prevent clogging>> This will not be cost effective. <<Not as is, I agree>> We use a softener, but I know after studying that this will not be acceptable for marine use either. <<Mmm...brings another question to mind...is the RO unit plumbed before or after the softener?>> I have looked at everything else on the market and am thinking about placing my last hope on the Kold Ster-il filter. <<Is an option...but I think you will find this unit too will need some pre-filtering with your source water>> I would like to find out your opinion on this product and if you think it would even be able to clean up my source water to an acceptable level. <<It is a good unit, and the exchange resin pad/material employed is an excellent product. But, I seem to recall something about issues with availability of the refill packs. If you decide on this unit, do try to contact the manufacturer re the continued availability/support of this unit/refills>> And if so, how would I then go about softening the water? <<...?>> Using peat? <<Ack!...no>> I know it will have to be softened some or I will never be able to get the pH up where it needs to be, without leaving the DKH through the roof. <<If whichever filter method you settle on is plumbed in after your water softener unit...excessive calcium/alkaline material shouldn't be a problem. But before doing anything, please take a hardness measurement, post filter unit, and get back to me to discuss options>> My husband usually figures these kinds of things out...but he is currently playing in Iraq's sandbox. <<Oh!...am a 20-year veteran myself (Air Force) and know how trying these separations can be...especially in these times. I hope he soon finds his way back to you, safe and sound>> Therefore, I really appreciate your time and help! Karen <<Karen, please do write back to me with more details of your RO unit (prefilters, how/where it is plumbed in, etc...whatever you can tell me) and lets see if we cant make this work for you. Regards, Eric Russell>>

Re: My Liquid Rock Is Clogging My RO Membrane! 06/08/07 Mr. Russell, <<Hello Karen...and please, just Eric>> Thank you so much for your reply. <<Quite welcome>> It is wonderful to be getting help from "one of the family" so to speak. <<Mmm, must admit to missing that special camaraderie among active-duty service members>> However, I guess I will have to apologize for not being Air Force! <<Hee-hee! We cant all be perfect...[big grin] >> My husband is Army and will himself, retire in July 2009. <<Mmm...and now the seconds are like hours...>> Currently on second Iraq tour. Fifteen months is indeed a very long time. <<This evening I shall drink a toast to his speedy return>> He is a maintenance test pilot on Blackhawks and is currently attached to a medivac unit a little north of Baghdad. <<I see>> At least my interest in marine aquariums helps to take my mind off where he is some. <<Ah, good>> Which brings me to answering your questions. Yes sir, I am indeed using a prefilter on the main incoming line. Then the water goes to the water softener. From there it went to the RO Unit, which also had the prefilter. It was a standard 3 canister type. I believe it was made by Whirlpool. <<Mmm, yes...purchased at Lowes? Should have been sufficient...obviously your water situation is at the extreme>> As for the hardness measurement, all I have to give you at this point is what the reading is after the water is softened (a lot) as we removed the RO filter. (Incidentally, I have freshwater fish. Don't ask me how, but they do live in this water and do very well for years.... Angels, Gouramis.) <<Tough, adaptable creatures>> After softening the dKH is in the 7-9 range. <<A good starting point for your marine system...and was very likely lower than this after the RO unit>> Never seem to get the same reading twice. But I have read that wells change constantly. <<With rise and fall of the water table, agricultural activity, rainfall amounts, etc...agreed>> Could this be brought down further by adjusting the softener itself? <<Not necessary...for your marine tank>> As far as the water straight from the well, we had it professionally tested a few years back, and it was literally off their test scale. Without being softened, the water will destroy a water heater in less than a year. Just rusts it clean through. Same on all metal pipe fittings. <<Yeeikes! That's some galvanic reaction you have going there. Only guessing here, but there must be an awful lot of magnesium in this water...>> We had to re-plumb everything to plastic. <<And yet this water is safe/potable? Amazing...>> I have really researched my other options such as the Kold Ster-il Unit because I just don't see how I am going to be able to get a RO Unit to work for enough gallons to make it worth the expense. <<Yes indeed...I can only speculate, but perhaps your water softener system is not designed/sized/suited for your situation...Bob, have you any comment re?>> I am so sorry that I am not more knowledgeable on this situation, but I am trying very hard to learn. <<No worries my dear, just keep plugging away!>> I really appreciate your time and effort to help me. <<Is my pleasure to share>> Please let me know if I can answer any other questions that might help us figure this out. Sincerely, Karen <<Im not convinced the Kold Ster-il unit wont clog/require frequent cartridge/media changes as well. Please have a good read here (http://www.wetwebmedia.com/koldsterilfaqs.htm) and do follow/read among the links at the top of the page re the different filtration options. Im beginning the think maybe a large, regenerable, Kati-Ani DI unit might be the best option for your situation. If you have any more questions or you're just ready/want to discuss matters further...you know where to find me. Be chatting, EricR>>

Coral <sic> Health 3/3/07 Hi Guys, <Hello Joe> I have a 135 gallon Reef Tank that has been set up and running successfully for over 9 months. Just three days ago, a large colt coral and a mushroom that were doing very well for over 6 months started to die. The Colt Coral has all but withered away (In 3 Days!). I noticed the mushrooms starting to detach in the past 24 hours. What could be causing all these issues all of a sudden? I haven't changed I do or added anything to the tank in several months (except a Coral Beauty 2 weeks ago. But he has shown no interest in any of the corals). I do 25 % water changes every 30 days. <Part of your problem may lie here. I believe too much of a change in water parameters at once, especially if the water chemistry is not closely matched to the display tank. I'd rather see you with 5% weekly or 10% twice monthly.> PH - 8.2 Ammonia and Nitrite zero Calcium - 450-500 I use Kalkwasser for top off water (RO unit) Once a week I add Kent's: Iodine, Strontium, Magnesium, Essential Elements I add Kent Calcium A & B daily Lights are 3 - 150 watt Halides (about a year old) and 4 - 96 watt Actinic Blue's. <How old are the lamps, the color temperature may have shifted. On another note, are there any cleaning sprays, etc, that are used in the area of the tank, ammonia based cleaners such as Windex?> Protein Skimmer working fine I hate these "mystery" problems. Any help you can give would be appreciated so I can avoid this problem moving forward. <I'd check the water chemistry of the make-up water before you add the salt, may be something amiss here.> Thanks, <You're welcome. James (Salty Dog)> Joe

Re: Coral Health 3/4/07 Thanks for the help. You mentioned testing the RO water before adding salt. What should I be testing for? Could I use my saltwater test equipment? <If you have a local pure water store, I would take a sample of your RO water there and have it tested for total dissolved solids. This will ensure that your RO unit is working properly. Most importantly, ensure the water chemistry of the new mix is very close to the chemistry in the display tank.> Thanks, <You're welcome. James (Salty Dog)> Joe

Ready For A BTA And pH Questions 1/10/07 Good afternoon Crew, <Good evening Brandon> I have two quick questions for you guys and gals. I have a 55 gallon reef tank that has been up and running for about 3 months now. Water quality is better then I have thought it could be after this little time. NH4/NH3 = 0, NO2 = 0 and NO3 = 0. I had to test with two different test kits because I did not believe it. My Ca = 450ppm and 12 dKH. My PH is about 8.3 with my new Hanna Test pen that I got for X-mas. I have been running around testing everything that is liquid to play with it and found something odd. My RO/DI unit is putting out water at a PH of 9.0 Is that normal? <Seems high to me. Did you calibrate your tester with a pH 8.0 solution?. For measuring freshwater, it is advisable to calibrate with a 7.0 pH solution. The tip should also be cleaned after every test.> I would figure it would be closer to 7 if anything. I am battling a bit of a hair algae problem but I just introduced the first major clean up crew this past week and they seem to be putting a dent in it (5 Emerald crabs, 25 Astrea snails, 10 Cerith snails, 20 Scarlet hermits and 20 Blue leg hermits. I suspect that my test levels are so low because any NO3 in my tank is being eaten by the hair and not being tested. My lighting is 4 x 65W PC lights with 2 12,000K and 2 Blue. I put a 2 X 35W PC on from time to time with 10,000K lights but it does not fit too well under the canopy and makes the back of the tank look yellow. With the normal 65W lights and pretty good flow (closed system from the sump running a Mag 9 with an output of 3 1/2" flare bars) and a BTA place at least 1/2 way up the tank, Do you think this is proper for a BTA? <A good start, but the BTA is going to move to an area of his liking.> No corals are in the tank and will not be for quite sometime if ever. I am kind of afraid of corals! :) <Shouldn't mix corals with anemones to begin with.> I just want to make sure I can provide a good home for a BTA before I get him but I would like to get him soon before my wife drives me crazy with her whining about a place for her clowns to try to make home. <Those pesky wives. Depending on what species clowns you have, they may not go into the BTA. On another note, if the clowns were tank bred, they may not go into any anemone as they were not raised with one, or do not know what they are. Your lighting should be sufficient for keeping a BTA. Read here and linked files above for more info. http://www.wetwebmedia.com/marine/inverts/cnidaria/anthozoa/bubbletipanemones.htm> Thanks as always for the sound advice! <You're welcome. James (Salty Dog)> Brandon

Re: A BTA Question And pH 1/12/07 James, <Brandon> Thanks for the quick reply. <You're welcome.> To clarify, I calibrated the pen utilizing a two step calibration with 4.01 and 7.01 buffer solution. <For sea water, I would calibrate with a 7.01 and 10.01 solution.> I clean the Pen (Running it through fresh water) after each use and store it wet as per the instructions. <I would clean in distilled water.> I am not sure if it is just my imagination or if I remember reading through the FAQ a while back about false PH levels with RO/DI water that has not been at least buffered (baking soda added). Am I imagining things or did I read that somewhere? <Mmmm, pH meters/test kits read the hydrogen ion level in the water. I don't see how not having a buffer could affect this. If you use a dechloraminator in your make-up water, this can/will alter your pH reading. I would suggest you present your questions to the manufacturer of the test pen.> My tank detects normal readings (8.2-8.4). One last question. I keep my Specific gravity at 1.023 +/- .001. Should I raise this now that I have added inverts and if I add the BTA? <No, not necessary.> As for the clowns taking to the BTA. I have warned my wife that her "Nemo Dream" might not come true with her false Percs and the BTA. She is willing to risk it and then replied, "If they do not take, aren't there shrimp and crabs you can buy that will live in it?" I just sigh! When I let her know that the BTA will move where it wants rather then where she wants (He will not jump for her like I do! :) ) She is ok with it.. Plus if the clowns do not take to it, I might move into the BTA to escape my wife! LOL <Yes, there are some crabs/shrimp that live in anemones, but again, they have their preferences also.> Thanks again for all the fun/good/hard/life devoting work ya'll do, <You're welcome. James (Salty Dog)> Brandon

TDS 1/7/07 Hello, "<Hi Ryan, Pufferpunk again> One question regarding your reply. What exactly does this mean, I will copy and paste part of my previous email so you know exactly what I'm talking about. Ammonia 0, nitrite 0, nitrate <5 ppm, temp. 78, salinity 1.024, calcium 450, alk. 10 DKH, and phosphate <0.1. I do water changes every week 10-15% with deionized water. <Have you checked the TDS on there lately? I like RODI, myself.>" So what I am not sure about is TDS, what is that exactly? <Total Dissolved Solids. This is what you want removed by a RODI system. When the filters get old, TDS leak through & you can have problems.> I will explain my water a little better. I work at a LFS where we premix the saltwater, which is now run first through a carbon filter, then a deionization unit and then through yet another deionization unit. So as you can see the water is extremely clean, also void of any minerals until we add the salt. All of this filtration equipment is setup and maintained by a professional company, this is not a DIY system. So although more striped of minerals and other beneficial things there is absolutely nothing bad in the water. The filter company says that RO alone only removes 90% of the bad stuff and this removes 99%. So when I said I used deionized water perhaps I should have been a little more specific. <Sounds good.> One other thing, I am confused by your choice in a course of action, typically chemical treatments are not something you recommend. I am not saying I disagree just a little surprised. <I am one that is generally against using any kind of meds, especially in my main tank. When I had a big Cyano problem, I tried everything you did. I was very reluctant to try this chemical but everyone assured me it was safe. I have to agree & it cleared up my Cyano problem after 2 applications--no harm done to my tank at all. ~PP> Thanks, Ryan. Hopefully you receive our previous questions and answers, my email seems a little funny today. <Your other emails will probably get directed by another of our Crew.> Measuring pH of RO/DI Water - 12/05/06 I recently started using a Typhoon III unit and just noticed that the pure water, which is stored in a Brute can, shows a pH of 8.6 on my FasTest test kit. <<An erroneous reading hobbyist test kits (and meters) have trouble accurately measuring the pH of pure water. Because the water contains no buffer, it reacts quickly and erratically with the reagents of the test kits/trace impurities on the test probes>> This hardly seems normal to me and I proceeded to test the water straight from the unit, which also showed this same high reading. <<Indeed>> I have heard in the past that some test kits get thrown off by pure water and am wondering if this could be the case or if there is a problem. <<No problem here and really no need to be concerned with the pH of the RO/DI water. Regardless of pH, adding the water to your system will likely be of little/no consequence where pH is concerned>> Just wondering if it is ok to use this water as the pH seems to be lower in my premixed saltwater (around 8.4). <<No problem at all. Carbonates behave differently in pure freshwater as opposed to saltwater believe it or not, there's even a possibility that adding the pure RO/DI water could raise your pH. My point here is this don't sweat the pH of your RO/DI water>> By the way my tap water does not show this high reading. <<Regards, EricR>>

Two topics: pH of RO\DI and Amquel+ 11/21/06 Good morning crew, I have two topics that I need assistance with. After reading Bob Fenner's article on 'Treating Tap/Source-water for Marine Aquarium Use'. I was worried about Amquel+ product that I use for removing chlorine and chloramines from my filter socks after treating them in bleach solution to clean. With the smell of the product it makes me believe it has formaldehyde in it. What is the general thought on this product and is there a product I should use in its place to remove chlorine? <Is a worthwhile product..., safe, effective... rarely going "bad"> Our water is sooo hard in our area and I have a water softener before the RO system to soften it. My RO\DI system produces water that has 9.1 PH before aerating. <Mmmmm> After aerating and adding Seachem Reef Buffer the PH is at 8.89. I replace the filters on the RO every 3-4 months and the membrane every 20-24 months. I have calibrated the pen and have a tank PH of 8.11-8.16 that has a calc reactor dosing it. Is the pen bad possibly? <Mmm, doubtful... you do calibrate it, check it against/with solution/s of known pH I take it> I did a test on 24 gallons of RO\DI water, after aerating it for 24 hours I added the buffer\baking soda till the PH reached 8.2. After 24 hours I added Reef Crystals salt to the water and CABLAMMY everything 'snowed' out of the water and the ph went to 7.65. <... I would aerate the new water for a day or more... mix the salt in, allow to run another day or more, THEN do whatever adjustment to chemistry/physics> The reason I did this was my calcium levels never improved above 280-290. <...? In the newly made-up seawater?> And feared that my top off water and water change mixture was hurting the tank. <Something/s is/are amiss here...> I am left to believe that my PH pen is giving me untrue measurements, but reproducible readings. What are your thoughts on this 'Phooey observation? As always thank you for your time. Dave <Time to "check the checker"... Perhaps a visit to the LFS where they can gauge your readings against theirs. Also... I would try eliminating the water softener in your tap/source water treatment path here... even just to see what the consequent water chemistry reads. Bob Fenner>

Testing RO Water 11/21/06 Dear WWM Crew, <Hi Helana, JustinN with you tonight.> I searched through your site to find an answer to the following question: IS there a way to test RO water to be sure it is RO water and not just tap/combo water? <Sure, a good quality TDS (total dissolved solids) meter.> The reason being, I purchase my RO water in buckets for a few bucks, but I'm wondering if this is really RO water? <A valid concern> I have all the basic chemical tests for ammonia, pH, nitrates, nitrites, alkalinity, calcium, etc. Would any of these confirm that it is RO water, or is there something else I could use to test it? Thanks, Helana. <None of these tests would reveal the purity of the water, but a good TDS meter is simple to use and will give accurate results. Depending on your water consumption, a good RO unit of your own, such as the ones available from www.purelyh2o.com would be a good investment. They consequently sell a complete RO/DI unit that includes a TDS meter for a very reasonable price. Hope this helps you! -JustinN>

RO and leaks 11/18/06 I recently purchased a reverse osmosis unit. I set it up and it was working fine, but I got a call from the owner of my building telling me that there was a leak downstairs directly below the faucet where I have the RO hooked up. I, of course, immediately disconnected the RO, and when I talked to him a couple hours later, he said the leaks had stopped. So it would seem that the leaks are being caused by my RO unit, but I can't understand how that could be. <I'm no plumber, but bad pipes seem to be the issue.> I would have thought the pipes would be at maximal pressure when the faucet is totally off, and that connecting the RO would actually cause a slight drop in pressure. I realize that you're not plumbers, but I thought one of you might be able to explain the problem to me, since it is related to aquarium gear. Thanks. <I would guess that the back-pressure of the RO faucet value us causing the leaks in poor/old pipe seals. Maybe try to talk the landlord into hiring a plumber to take a look, may indicate more serious problems.> <Chris>

Nitrate, nitrite, hardness, alkalinity, pH of RO water? - 11/13/06 hello WWM crew, <Capitalization?> I just installed a Coralife Pure-Flo 76000 3-stage 24gpd RO unit. I've attached it to a hose bib on the side of the house that runs cold water with plenty of pressure. I also attached a Coralife float-valve unit to the system and the RO water is being held in a 25 gallon reservoir. I've made 50 gallons with it and tested the water at all points on the RO system. the unit seems to be mechanically functioning correctly. there are some issues which are raising my curiosity: - first, the unit produces 25 gallons in 2 hours? <That's quick... likely just from being new> - second, when I test the RO water with a Hanna TDS meter, it reads at around 200 ppm? <Oops... maybe the same reason... you should vent the first few batches... test again> - third, when I test the RO water right after it has been made with a 5-in-1 test strip, the readings are: 8.2 pH, 200 ppm alkalinity, 120 ppm hardness, 2 ppm nitrite, and 80 ppm nitrate. <... see above> when I test the RO water with a 5-in-1 test strip after 24 hours, I get 7.2 pH, 120 ppm alkalinity, 120 ppm hardness, 0 ppm nitrates, and 0 ppm nitrites. <Just interaction of chemical species here> I've repeated the testing several times. is this normal? if so, why does it change over 24 hours? what should normal readings be for RO water in terms of nitrites, nitrates, pH, hardness, alkalinity? thanks very much, Chris- <Chris... Strunk and White... get it, read it, live it... or don't write back. BobF>
Re: nitrate, nitrite, hardness, alkalinity, pH of RO water? 11/14/06
Thanks for the quick reply. Looks like I have a larger problem with my grammar than I do with my RO unit! <Heeee! But getting much better!> When I test my RO water, what should the results look like? Should I see low PPM, low pH, low Alkalinity, etc...? Chris- <Low TDS (less than 10 ppm), a bit low pH (high sixes) going back to near neutral (7.0) over time, aeration, almost no alkalinity (less than 1 meq/l). You have searched, read on WWM re? Bob Fenner>

RO/DI not removing phosphate 11/25/05 Hi Guys, I am trying to figure out the origin of my problem. I recently purchased Pure-Flo II RO/DI Unit - 50 GPD TFC - 3 Canister and having troubles with it. So far I can only see that there is something wrong but I can't identify where exactly. So here what I have. Before attaching this unit to the water source I rinsed the carbon block for about 15 minutes under the stream of cold tap water in order to remove the trace of a phosphoric acid. After that I attached the unit to the water source. My tap water has Phosphates reading of 0.5 ppm. I discarded first 15 gallons of water and then produced additional 5 gallons to make a partial water change in my tank. After I did the water change, ~ 10% of my tank volume, next day I observed the boom of assorted algae. The phosphate and silicate readings in the tank are 0(I am using Salifert test kits). But how I was surprised when I observed that they are not zero in the RO/DI water that I made. In fact the level of phosphates is the same as the one in the tap water. Which made me think that the unit operates incorrectly or I am doing something wrong. Thanks in Advance. Alex <I would contact the company for support on this issue, but in brief... as you obviously know, carbon blocks often contain residual phosphoric acid. I would suggest testing a sample of water that has passed through the carbon, but not through the RO or DI. I suspect that you will find that the phosphates are off the chart. Under normal circumstances, RO/DI will adequately reduce phosphate, but when such high concentrations are present coming in, some is going to make it through. You will most likely have to replace the carbon blocks with pre-rinsed ones to solve this issue.> Tank Info: 30G FOWLR, Remora Aqua C with MaxiJet, Lunarlight 2x65 PC/Actinic, MaxiJet 1200, Hagen power head 30, Fluval 204 (cleaned on daily basis), ~20 lb of LR, no fish no inverts but some kind of worms and insects that came probably with LR, still cycling. Water parameters: Ammonia 0.25 (used to be 0 last Friday), Nitrite 0, Nitrate 5, Phosphate 0, Silicate 0, Ph. 8.3, Calcium 400. <All sounds good! Best Regards. AdamC.>

RO/DI unit membrane change - 5/8/2006 At which TDS reading should one change the membrane of a RO/DI unit? I've had my unit for just over a year and my reading on my meter reads 75ppm IN, and 40ppm out. I tried flushing out my membrane several times. I'm thinking this is what is contributing to my Cyano problems. I've eliminated all other reasons Cyano. What do you guys think? Nilesh <Nilesh - Assuming your TDS meter works fine, most people strive for an output of 0-3ppm. Thus, 40ppm is quite high. After 6 months to 1 year, many manufacturers recommend changing all the filters/membranes. However, it really depends on the system, overall use, and your water supply. If you had been testing with the TDS meter since the beginning, you could have seen the water level decline over time and be more certain that you need to change the filters/membranes. At this point, I would suggest making sure the TDS meter is working properly by checking it with distilled water (it should be close to 0ppm). If it is, contact the RO/DI manufacturer and see what they recommend you replace. My guess is that without being able to test each component individually, they are going to recommend replacing all of the filters/membranes. If so, then you can test the output with your TDS meter and develop a baseline to monitor over time. Due to variations in water supply and plumbing, everyone's input and output TDS readings are different. However, the input TDS should remain relatively constant for you over the course of the year. Once you know your individual situation, you'll be able to figure out how often to change the components going forward. Best of luck, Roy>

RO System Output...Possibly Damaged or Faulty Membranes - 09/27/06 I am having a problem with my RO system. <<Oh?>> I have a Kent 200gpd system with an add-on DI. <<Big system>> I store all in a 200G plastic tank. After replacing all the cartridges (including membranes) it will run great with the TDS reading 0. <<Good...>> But within about a month I notice that the RO unit is producing water much faster than usual (it normally produce about 125-150gpd) and the TDS is up to about 140 which is about the same as tap water. <<Mmm...not so good...>> I change the sediment and carbon prefilter about every 7-10 days, because I read you should change them every two to three thousand gallons. <<And you produce that much filtered water in a week?...wow>> It seems as if the membranes are failing. <<Indeed...am in agreement>> Any help would be appreciated. <<A couple things come to mind...Firstly, I would try a different source for obtaining membranes. Next, make sure you are getting 'TFC' membranes as opposed to 'CTA' membranes. The CTA membranes break down very quickly if exposed to chlorine, and if your carbon prefilter is not adequate at removing this, well... Also, rather than using the sediment prefilter, consider using "micron rated" solid carbon blocks. Using a 5-micron block as your first-stage and a 1-micron block as your second-stage will still filter out particulates while providing some additional chemical prefiltering of the water before it reaches the membrane. Most carbon block combinations such as this will usually give you in excess of 5,000 gallons usage, and I seem to recall some with 30,000 gallon usage ratings (these blocks can also be easily rinsed of loose sediment on a weekly/monthly basis)>> Thanks, Daniel <<Hope this proves helpful. Regards, EricR>>

How to recharge a deionizer I've looked and looked but haven't found anyone who will lay out step by step how to recharge a deionizer. I know you first have to have one that is rechargeable. any help? thanks Brian <Mmmm, well... some resins are recharged with caustic substances... some with salts... Some can't be economically recharged by simple soaking (require high pressure, temperature in the process). My real advice is to contact the manufacturer or barring this, find out the name of the ion-exchange resins in your unit and search the Net, reference works in a large (college) library re this issue. Bob Fenner>

- RO Filter Changes, and More - Hi there how are you, I have a couple of questions. <I am well... I will try my best to answer your questions.> how do I know when it is time to replace the filters on a RO unit, I have the Coralife unit with a 1 micron filter, carbon. sediment filter. <There are no hard-set rules, but six months for the micron filter is pretty good - if you change this filter often you can extend the life of the other cartridges. Typically the micron filter is the cheapest in the bunch.> I was told that when the output slows down that you need to replace the filters, my question is do you only replace some of the filters or all of them? <I personally don't wait that long, and my RO unit has clear filter cartridges so it's possible to see when the micron cartridge is getting loaded up with particulates. I've moved a lot in the past year and a half and have found that the mileage on these filters varies greatly.> or is there a better way of knowing when to replace the filters, they are rather expensive so I would like to be sure. <Well, for certain they don't last forever so... you just need to keep an eye on things.> Can you test the water coming out of the RO unit, like if the hardness goes up is this a sign or can you recommend me the best way to know when to replace the filters, also I only use 15 to 20 gallons a week so I shut off the RO unit when not in use, I was told that's its not good for the filter if it is shut off, is this true? <I've not heard this, can't verify it's truth but have shut my filter down many times, in fact right this minute it is doing nothing... think this is in fact pretty standard - as in I don't know anyone who's RO system is running 24/7.> I leave the hoses above the filter so the water does not drain out. <Sounds fine to me.> If I don't need a lot of water why keep it going is this OK to do. <I wouldn't be too worried about it.> I would like to store some of it also. If I used Rubbermaid containers say a couple of 20 gallons how long could I store it for with no air stones or powerheads, or this not a good idea. <It's not good to store water without some form of circulation... it will go stale relatively quickly.> my other question is about the PolyFilter by bio marine, good product, but when do I know when it is time to change it the instructions say you can wash it and reuse it, but I thought I read somewhere on your site that they cant be re-used, also since it is a little expensive how often would you recommend using it. <The Polyfilter is supposed to change colors as it absorbs undesirable chemical compounds. I wouldn't run one of these all the time if cost is an issue - instead just use normal filter pads if all you need is physical filtration. A Polyfilter is both physical and chemical filtration.> my parameters are pretty good, would I still use it even if everything is Ok, or only when I have high ammonia readings, also does the PolyFilter remove trace elements or just the bad stuff, I heard that it wont remove elements out of the salt but will remove any supplements I add to my tank. <It will remove some but not all... but if you're dealing with high ammonia issues, I wouldn't be using a Polyfilter but instead attack the problems at the source.> thanks for your help in advance, your site has been very helpful. Val Toronto, Canada <Cheers, J -- >

Update on Austin water Hey, WWM-ites, <Hello Glen!> I went and got some RO water here in Austin yesterday, and ran my battery of tests against it. The machine at the grocery store was showing that it had last been serviced on 11-6-04, and the store manager said it wasn't very heavily used. Based on that limited info, I'm assuming that the media are still in good enough shape to reflect what would happen with an average RO system here. <... not according to the results you post below... something is definitely awry> As I expected, the pH wasn't any different from our tap water. The RO water settled at pH 10.0 <What? If anything, a functional R.O. device may show a drop in pH (below neutral)... Please see here: http://www.freedrinkingwater.com/water-education2/ro-ph.htm Virtually all bicarbonate and carbonate is removed by reverse osmosis.> on my meter, and a sample of tap water at the house registered pH 9.9. kH and GH of the RO water registered zero with both the dip-strip and reagent tests, compared to the tap water's 3 dKH with reagent and <75 ppm kH and ~80 ppm GH with the dip strip. Temperature of both samples was 71F. <This is about right where it should be...> Also, for what it's worth (if it's salient to the total osmotic pressure discussion) the City reports TDS at average 184 ppm in September (the last reported month) and for the third quarter of '04. <Okay> Interesting results - RO here has all the "stuff" removed from it, but still has to be treated fairly aggressively to bring the pH down to neutral, and then buffered to stabilize it (right?). <... should not have to be treated for pH at all... I would check your testing gear (against standards, use other means...)... aerating it should register a near neutral pH over an hours time or so. Does indeed have to have alkaline material added to re-buffer.> Thanks again for having such a fantastic trove of info for those of us who are a bit less informed! Glen
Re: Update on Austin water
Not to be argumentative, but 'cuz I truly want to understand... <Me too> I calibrated my pH meter to a 7.01 and 5.01 standard a week and a half ago, and the tank readings have been holding pretty steady (up 0.11 - the tank is just slightly into its cycle - ammonia reading ~0.5, nitrites and nitrates still 0). The City reports an average total alkalinity at the tap of 60, and a total hardness of 86, which are in line with my not-very-sensitive test kits. Doesn't this indicate that there isn't much carbonate or bicarbonate to begin with? <Depends on relative measures, what you call "not much"... this is considerable if it is coming out of an R.O. unit, about so-so for U.S. tapwater... and very hard for general Amazonian comparison...> I called our LFS a minute ago, and was told that their RO pH is nearly identical (a couple of tenths lower) to their tap water, at 9.2-9.4 (they draw from a different aquifer, and the slightly lower pH is in line with the City's reports). <Strange... or maybe I should state, unfamiliar to me... our R.O. water has a pH of nearly 7.0, with the source water (San Diego) at 8.2-8.4 most days> I know that y'all's water treatment FAQ says that aeration would raise a slightly acidic pH out of a RO system to neutral, by neutralizing the carbonic acid - will it also drop a pH three points? <Not easily... depending on what (carbonate likely at this high a pH) is elevating the pH, and if there is any alkaline reserve (buffer aka) at this high pH...> If not, does the approach I asked about in yesterday's question (titled "Plan of attack for very soft, very basic tap water") make sense? <Am copying and pasting a pertinent part of this here: "Here's my approach to the water. Please let me know if there's something I should do differently: 1. 20% water changes once a week, with substrate vacuuming. 2. Dechloraminate 20-25 gallons at a time (in a dedicated new trash can) - easier and more uniform to treat a bunch all at once. 3. Bring the pH down to 7.0 (using the sodium biphosphate product (anything better?)). 4. Boost the kH and GH into more the 125 ppm range using calcium carbonate. (Would something else, or a different value, be better? If we actually adhere to this rate of water replacement, does our tap water need additional buffering, or is the little bit that's there going to be enough?) 5. Aerate and tweak temperature overnight before a water change. 6. Judicious chemistry monitoring between changes. Since RO water still needs to be tweaked with pH adjustment, buffer, and essential minerals - why not adjust the tap water? Also, I bet the pH of RO water around here is still quite high, given the tap water to start with - I'm going to get a gallon on the way home and test it. Also, since the tap water is so soft to begin with, the double-whammy of a buffer and an acidic product shouldn't have too much impact on osmotic pressure, right?" This does sound like a logical, workable plan... am still very curious as to what is "getting through" your Reverse Osmosis membrane that is resulting in such high pH though...> I don't mind tweaking the water as necessary, but don't want to osmotically stress the fish. Thanks again for your time, Glen <You are right to be concerned re osmotic shock... Do me/us a favor and call your water supplier (their phone number will be on the bill they mail you) and ask to speak with someone in water chemistry there. Please explain what you have here, and ask what they think is going on with your resultant pH. Bob Fenner>
Re: Austin water dept. chemist discussion
Well, that stumped 'em. <Umm, me too... maybe we can start a club...> I talked to the City's chemist, and he was surprised as well that the pH stays that high after reverse osmosis. He said that the output of their deionization system (when they make their reagent-grade water) gives them a pH of 5.5 to 6 (as it's supposed to). <Yes, agreed> He said he's not intimately familiar with how RO systems perform here, but he doesn't see any reason why the RO water still carries such a high pH. His guess was that given the high concentration of hydroxyl ions, it's possible the RO system is being overwhelmed, and suggested that someone test the very first dribble out of a new RO cartridge to see if it reads closer to neutral. <... hee heee... am given to suggest that your source water has a good deal of "hydroxyl" ion concentration... turns out that most brand X R.O. membranes allow ethanol/C2H5OH (and Glycol if interested) through... do you feel elated after a big glass of tap? Hey, maybe that's why it's called a "tap?". Just joshing here... and things change... I was a H.S.... Physics and Chemistry teacher years back... but OH's (Hydroxyls) are otherwise given the suffix "ol"... as in alcohol...> The chemist also said they treat the water at the plant with calcium oxide to cut the sources' hardness from 185-200 down into the 85 range. That explains why our tap water doesn't fit the usual high pH/hard water "norm" - it comes somewhat pre-softened. From the reports, the source water is also around 170 ppm kH, where the tap is down around 60. <Ahh, yes> I called the LFS again and they said their RO water always has a pH above 9, though they've never tested it's initial output. Another LFS backed up the tale - RO pH is never below 8.5, and almost always over 9. <I believe you, them... am just at a loss to explain why/how this is happening. Hopefully some kindred chemistry soul will see our correspondence posted on WWM and chime in> All the more reason to be religious about water changes, and not put in more additives than absolutely necessary, huh? Thank goodness for a wife who's interested in aquariums, too! <You lucky pug! Mine is kind enough to go and photograph on dive trips, even liveaboards, even though she is easily boat/motion sick> Once again, thank you for your site and your input. I really like your rational, cautious, livestock-oriented approach to the subject. Glen <Me too! Be chatting, Bob Fenner>

High Phosphate in RO water 8/12/05 Hello everyone, I'm a newbie to saltwater and I recently set up a 155 gallon reef tank. In this time I've had trouble controlling my phosphate levels. Here are my specs: 1. 155 gal tank 2. Lightly stocked tank with 1 purple tang, 1 six line wrasse, 1 clown, 1 lawnmower blenny, 2 cleaner shrimps. 3. 2 mushrooms, 2 rocks of yellow polyps, 1 green star polyp. 4. Two overflow boxes, aqua C ev-180 skimmer which produces lots of crap daily. I use RO/DI water weekly and perform a 10 % water change every week. My RO system is from Coralife-pure-flo. 4.All water parameters are normal except the phosphate level which is a whopping 1 ppm with the Salifert test! I thought for the last three months that the levels were high because I was feeding too much but I wasn't. Sometimes I would actually skip a day so my fish could graze on the little hair algae I have in the tank. I then thought that my test kit was wrong, so I bought a new Salifert test kit. Anyways, I decided to test my RO/DI water without salt straight from the tube and the phosphate levels measured 1ppm! I then checked my TAP water from my faucet and it tested only 0.1 ppm. I retested all my different waters and the results were the same. I came to the conclusion that it seems like my unit is leaching out phosphate, is this possible? The RO/DI unit is very new, I bought it 5 months ago and according to the instructions, the pre-filter needs to be changed in a months time and the membrane should last another 6 months. So I still have time for change. Any thoughts? Nilesh <This is an easy one! Activated carbon is made porous in the manufacturing process by exposing it to phosphoric acid. If the carbon is not rinsed, it will leach phosphates in high concentration, much of which will pass through the RO membrane. If you really want a shock, test the water coming directly out of the carbon block pre-filter! The simplest option is to replace the pre-filters with good quality aquarium brand (something other than Coralife!). Prefilters should be changed every six months to a year, but the membrane itself should last several years. Best Regards. AdamC.>

RO product water = 4.0 ppm P04!!!!!!!!!!! Hey Guys! I've been having some problems w/ phosphate levels the past 3 months. I was reviewing your site today (awesome information, by the way) and realized that my problem may be the water source. <Ta da!> I bought a RO unit about the same time my problem started. After testing the water from the unit, sure enough, the PO4 levels straight out of the unit are at 4 ppm! <Insert gagging face here> I immediately went to an on-line aquatics supply store, they had a ton of replacement filters, but nothing specifically for PO4 removal. I had no idea what to get. So my question is twofold: 1) can I even buy a replacement RO filter that will remove phosphate, and 2) if so, do you know which one I should purchase? I spent too much on that dang thing, not to be able to use it! <Are you sure you're using a reverse osmosis unit? With even the cheapest R/O unit you should have undetectable levels of phosphate in the product water. Your unit should have a sediment filter and carbon block before the membrane. It would also be a good idea to purchase a post deionizer for the product water of the RO. If you care to send me the specs of your unit, I'd be happy to make specific recommendations. -Kevin> Your help would be greatly appreciated. Mike
- 4ppm PO4 R/O water part 2 -
Dear Kevin, Thanks for responding so quickly! Yea, the unit I bought is definitely an RO. Specifically, it's a 5-stage RO unit, the first cartridge is a sediment filter, followed by a pre-filter, a carbon filter, the membrane next, and finally a "water polisher." <Hmmmm, I wonder what that is...> Other than this, I'm not really sure of the specs; it looks like any other RO I've seen. It wasn't manufactured by a marine products company, e.g., Kent, et al., but I figured an RO is an RO, and so on. <Heh, don't worry, none of the marine products companies make any more than the stickers that they put on the units> I'm really at a loss as to why so much PO4 is coming through in this supposedly filtered water, and would like to get some filters to get it working right. 1/2 micron carbon filter perhaps? I'm not sure. <I'd swap out the water polisher thing for a DI resin, any brand should fit.> As a side note, last night after I wrote, I did a little experiment that you may be able to pass on. I have a lot of water stored-up that I obviously can't use so I had to get the phosphate out. I set up two 5 gallon buckets and filled them both with the RO water (this is water that's been through the unit, but still has a PO4 reading of 4). From 9 p.m.- 9a.m. I ran a Whisper over-the-tank power filter filled w/ Polyfill on one bucket, and put a submersible power filter that had a poly cartridge packed w/ Phosguard in the other. This morning, the bucket w/ the over-the-tank/no Phosguard still read close to 4 ppm, while the submersible w/Phosguard read about .15 ppm. I know that's still high for a SW tank, but is certainly better than 4! <Yes, it's still very high, but 4 ppm makes me want to puke> Regardless, I want to get my RO unit useable, without the extra Phosguard treatment. <Here's another experiment to do, remove the water polisher, make some water, and test it for phosphate. If it's still high, you need a new membrane. You can replace the polisher with a deionizer anytime, I'd do this right away. Good luck! -Kevin> Thanks for your advice, Mike
- More RO Phosphate -
Yea Kevin, that was a good idea to disconnect the "water polisher." I took a water sample w/o it, and the PO4 was still at the same levels, but replacing it with a deionizer is the way to go. <Mike, I wonder if it's your phosphate kit, although you did get a reasonable reading after running phosphate remover...> One last idea, the carbon filter is only a few months old, but if they get saturated, they can release phosphates, right? <No, but even so, the RO would take it all out.> Maybe, it's the culprit. Thanks for your help and suggestions; the WWM site as a whole is amazing. <Alright, here's my thoughts on this whole phosphate saga: If the water coming out of your membrane is high in phosphates, there are only four possible reasons. 1) Your phosphate kit is wrong, but I don't believe that is the case... 2) Your membrane is bad, used up, finished, done 3) you're discarding the product water and using the rejected water 4) the phosphate fairy is coming at night and sprinkling it into your RO reservoir. This reminds me, time to change my DI resin! Good luck, -Kevin>

High PH from RO? (7/8/03) I just purchased a new RO Unit... It is a Dolphin 100gpd unit from http://www.aquariumwaterfilters.com/RODI/Dolphin.html I tested the water with the free TDS meter they give you and it tested out fine at 4ppm. However the pH on this water is at a whopping 9!!!! Most RO water I've had experience with is at around 6. <Wow! That is strange, make sure your ph test is accurate, the liquid one get old and unreliable fast. See if your LFS will test it for you to be sure its not just the test kit. Also try testing your source water and see what that is. Cody><<RO water is often of low pH due to the high/er solubility of ambient carbon dioxide (which goes into solution as carbonic acid mostly) and the lack of neutralizing alkalinity (these minerals have been removed by the RO process...). If the pH is high... something is amiss with your RO unit. RMF>> Suggestions to why this is? Thanks, Sonny

-Recharging DI resin- hello all and happy long weekend- <Thanks, alas, it's all gone now...> I was hoping you could help me with a few questions regarding a Kati/Ani 2 set-up I just purchased from Dr. Fosters. I also purchased replacement color changing resins from SpectraPure for this same unit. I am now thinking this was a lack of knowledge induced mistake. I hope I can return them, they were a bit expensive. Now that I have the Kati/Ani units in my hand it looks like they are a sealed unit except for a little plug on the front. I am now thinking that you do not replace the resins inside and you just recharge them instead. Is this correct? <I just throw mine out when they're depleted. If you want to recharge them, check out http://www.reefs.org/library/article/twp_recharge.html>Or can they be replaced somehow also? <I'm sure there's a way to dump what's inside and replace with what you've bought. Check and see if that plug is removable.> From what I have read, it looks like I would use lye and Muriatic acid. Do the resins just get rinsed/soaked in these chemicals and reused again? <The chemicals should not be reused> Do you know if the recharged resins retain their color changing ability as they are exhausted ? <Yep, that's how you tell that they're in good shape (they'll be the original color)> I am guessing, yes. The instructions that came with the units are printed in somewhat of a broken English that makes me a bit unsure about the process. For hook-up ,the instructions talk about using Kati/Ani for" total desalting of water" and how to hook up the units. It shows tap water entering through the center of the Kati unit, then flows over to the center of the Ani unit and then out for storage. Is this the correct procedure? <I'm not sure how this brand goes together but you want all water to go through the resin without any possible bypass> I do not know what desalting means. <Just means stripping the water of all impurities> I apologize for all of the newbie questions regarding DI water but I do not want to make a mistake and hurt any of my longtime finned friends. <I hear ya, better safe than sorry!> Have a nice weekend and thank you for your time <Good luck! -Kevin> Dennis

- RO/DI Water Smell? - Hi, <Hello, JasonC here...> I have read all the topics about my problem in the section, but I did not find anything similar to my problem. I appreciate if you could give me some advise about this. Here is the problem: I have new Kent Marine RO/DI HIS 60, and it has made only 140 gallons of water for 10 days till now. I have disconnect the unit from the water supply for a 1-2 days and after that, when I connect it again I have noticed that water has some smell, I check for nitrate, phosphate and ammonia and there is none. I have used some of this water in my knew tank and now I'm a little afraid of what might happen. <Because some water stays in the filter, it is possible for the water to become stale and if prevailing conditions are right [heat, light, etc.] you can even begin to grow things in the filters. This is probably what happened in your case. I would first try putting some of this water into a bucket or garbage can and aerate it vigorously... see if the smell goes away. If that doesn't seem to help, I would try running 10 to 20 gallons to waste and see if the smell goes away. If not, you may need to disassemble the three cartridge filters, bleach them and replace the cartridges.><<May need to bleach/sterilize the cartridges... to eliminate microbes here. RMF>> I appreciate your help in advanced <If you plan to let this unit sit for any time, you should take it apart.> Regards <Cheers, J -- >
- RO/DI Water Smell? Follow-up -
Uhhh... that is a quick reply. Thank you. After aerating heavily I can hard noticed that smell. What are you suggesting to me, can I use that water or not? <I think so, sure.> The unit now creates a water with no smell, but the first block cartridge is, let me say black, not dirty. <Replace it.> Is possible that I must change it after 130 gallons of make up water. <Perhaps your source water is just really bad, so yes... it is possible that after 130 gallons that filter must be replaced.> Thanks again <Cheers, J -- >

- Odd RO Results - Got a strange water question, I looked around the site and have not seen a match. <Ok.> So, here goes.. The water coming out of my RO has a very high Ph reading like 8.4, thought this should be more like 7.0? <Something like that.> I have re-calibrated my Pin Point Ph monitor and get the same reading. This Ph reading does not seem to change with aeration over 48 hours. <Interesting.> If the Ph is 8.4 should I still add buffer before mixing in the salt? I have used my La Motte hardness test kit and the dKH is like 4. <It probably wouldn't hurt to buffer this water a little bit - shouldn't need to worry about the pH.> What gives? <Perhaps something is wrong, perhaps something in one of the cartridges, hard to know exactly but would move through a process of elimination to try and find out. Would start with testing your source water.> Brian <Cheers, J -- >

Kati Ani deionizer units 11/11/03 Hope all are well? <and you in kind, my friend> Anthony which of the Kati Ani unit did you buy & where can I find more info about them besides stern & foster also do you know who may sale them wholesale. <I have favored the "Kati Ani" brand for many years and purchased mine wholesale from a regional distributor in Maryland: Peter Thode at Gwynnbrook Farms - an old German discus breeder. I hope he is still around and in business (his son(s) were involved too). Nice folks> what does it cost to recharge units . <mere pennies per gallon with Muriatic acid and lye> One of your many friends in fish ROCKY <kind regards, Anthony>

Questions about R/O water and mixing salt 12/15/03 I have some questions about R/O water and mixing salt that I was hoping you could answer (I couldn't find the exact answers on your site): - How many PPM of TDS solids are acceptable in R/o water before the R/O membrane needs replacing? 5 PPM, 20 PPM, ??? <somewhere between the two in my opinion. I favor changing it by 10ppm> Is TDS and ppm the right thing to be checking to determine when the R/o membrane needs to be replaced? <good question. It depends on your use of the water. If you are using RO because you are breeding discus fishes, then TDS is a big deal (less is better here). But if your RO is for marines, many of the hardness minerals are actually desirable and we are instead using RO to rid nutrients/contaminants (metals, phosphate, etc). As such, you will want to test for things other than TDS> - I've noticed that my salt mixing tank will build up a brownish residue over months on the sides and on the aeration stones, heater. <may simply be a bacterial slime. Your vat is hardly sterile, and as such growths will develop in time> I use Rubbermaid tubs for my R/O tanks and salt mixing tank. the r/o tanks never get this residue, but the salt tanks do, and the only thing different in the salt tank is that it is aerated, heated with a titanium heater, and has salt (instant ocean). Any ideas on what causes the brown residue slim? Is it harmful? It looks almost like a rust, but comes off easily via wiping. <not harmful at all... if the vessel gets any indirect room light, the growth may also be diatoms> - Your site indicates that when mixing salt, you should: 1) get r/o water, 2) aerate it and heat it 3) add buffer to increase alk, and then 4) add salt. How much buffer should be added - enough to reach normal salt water alk? <yes... obey your test kit on this one. It will vary depending on the quality of RO water being produced> -lastly, I found a faq on your site that indicated saltwater plants (Caulerpa) could go thru a freshwater dip prior to quarantine (like fish). <some will, but many wont> How long should the dip last - and is this only for Caulerpa, or can most macro algae tolerate this (like Halimeda)? <very few will survive the osmotic shock of FW. Its best instead to simply quarantine all as you do your fish in a separate QT tank for 3-4 weeks before moving into the main display> thanks!<best regards, Anthony>
Questions about R/O water and mixing salt IV 12/22/03
Thanks for your reply, but I'm still a little confused about a couple of your answers: c) Is it correct to assume that TDS meters measure all dissolved solids (if there are 3ppm of phosphate in water, then the TDS must be at or above 3ppm)? > <I'm not sure that I understand the angle/intent of your question here? Especially in light of a marine aquarium with several hundred ppm of TDS> I'm talking strictly about R/O water. If the TDS meter reads 5 ppm in the R/O water, does that mean that any phosphate that might be in the R/O water would have to be less than or equal to 5ppm (does the TDS meter include phosphates in its ppm reading?). If so, does the TDS meter include just inorganic phosphates or organic as well. <Ahhh... I see. And frankly am not completely certain that I know the answer although I suspect that at least some phosphate (organic) is not reflected in this measure of solids. The correct answer though depends on the membrane (what they will or won't admit/pass). A call or look at the mfg specs will answer this question clearly mate> Also, you've indicated that you'd change r/o membranes for r/o water used in reef tanks if the water reached 5-10 ppm. because of this, I'm assuming those Kent r/o water TDS meters (black box) aren't useful because their most sensitive setting is 50 ppm. Is this correct? <Frankly... I don't use RO units (they waste obscene amounts of water... I prefer DI). And as a consumer, I do not hold most Kent products in high regard> You mentioned using Lux/par meters to get an objective assessment of the 'quality' of light being produced by bulbs. Can you recommend specific brands of quality PAR meters (and Lux meters)? <yes... "Apogee" brand PAR meters are popular with aquarists. A wide range of price and quality is available too> I've used Lux meters in the past, but they seem to be very sensitive/inaccurate (a small change in angle - <10 DEGREES - Can often double the reading). Thanks! The reason I'm asking these questions is I've had 2 75 gallon reef tanks running for a couple of years without problems. Over the past couple of months, both tanks have had similar problems: overgrowth with a Cyanobacteria-like algae that covers/suffocates the coralline algae. <many possible reasons for this> It is not like Cyanobacteria in that it is like tar - almost impossible to remove even with brushes. Fish seem fine, but all snails/crabs and corals have died (mushrooms, SPS, LPS, etc). I've checked/rechecked water quality, and everything seems fine: ammonia=0, nitrite/nitrate=0, calcium=400+, alk=8-10, ph=7.9-8.3. <the pH is way too low in my opinion... 8.3-8.6 is closer to NSW and regardless is known to inhibit many nuisance algae. 7.9-8.3 is also too wild of a swing between day and night (aeration deficiencies?)> Phosphates/silicates read 0 (SeaChem test kits). I'm at a loss to explain, but since it affected both tanks, I thought it could have been the pc bulbs (only 4 months old when this started) and have changed them w/o results. Also thought it might be my R/o water - but TDS meters (multiple) show it at 5 ppm. I've done massive multiple water changes - 40% - without any change in rate of this dang Cyanobacteria like growth. I've put in poly filters and SeaChem's PhosGuard w/o change (do these filter medias absorb only inorganic phosphate or both organic/inorganic) Any ideas? <inadequate water flow is commonly a catalyst (needing 10-20X minimum... and be sure to clean those pumps and powerheads with acid/vinegar every 4-5 months to achieve max water flow)> Thanks - from a coral reef fan who thought he knew what he was doing for a couple of years only to be demoralized by this latest setback. <no worries... can be easily corrected in time. Anthony>

- Lifespan of Deionization Cartridges - I'm considering purchasing a Kent Maxxima system. I can find lots of info on how frequently to change the various filters, except for the deionization resin filter. I can't find any info on how frequently these need to be changed. Do you know? <The 'amount' of time is a range, depending on the quality of the source water. Most DI cartridges change color as the resin in them is used up. That's the best way to know when to swap it out. Cheers, J -- >

- Odd RO Testing Results - Hi Bob, Anthony, et al.... I just got a new RO/DI unit very recently as I know my tap water has some issues. One issue is called mix it with salt, and it turns blue after it clouds to no end in a white bucket. <Something seems very wrong about that... what brand of salt is this?> The other issue is I suspect it has been a major contributor of phosphates in my tanks (fresh and salt). I flushed the unit for a few hours, and the pH coming out of the unit is higher than what goes in it. At first I was getting a reading of 10+ and I can't get anything better than either 8.5-9.0 after flushing for a few hours. <Wouldn't expect the pH to be much higher, should be in the range of about 7.0 - neutral after water has been filtered with RO.> After talking to fellow hobbyists with the same brand of unit or a unit in general we came to a few scenarios. One was called I screwed up my lines from the membrane, one was the manufacturer suggests a break in period, and the other is called the test kit won't work. <Or all three.> Someone else bought the same exact unit from the same exact person and tested the pH with a liquid freshwater kit, and got the same results. I did test the GH and KH of the water, and I don't get any color at all when adding drops to the water, so there is nothing that is readily jumping out at me that says this water has anything in it that would raise the pH. I don't have a TDS meter though I wish I had one. The manufacturer says this sounds like a break in issue, and just keep flushing the membrane. We have ruled out plumbing errors. I have read that testing pH for DI water is a real pain, and even with a digital meter it can be a pain as one can contaminate the probes, or CO2 in the air can throw it off. <Not that much - you should be able to test quite close to the actual number... CO2 and other contaminants should throw things off very little. Can let the probe sit in distilled water if you are concerned about the same.> If I have flushed the membrane for a few hours, and there is no sign of anything that would buffer that water, or otherwise raise the pH, do you see any way that the pH could actually be that high? <Hmm... my RO/DI break-in was supposed to be 100 gallons... would have taken several days to break in, not just a couple of hours.> I have tested the rejection water of the membrane and it yields the same results. However, the water is much clearer (I have a time seeing it in a container at times its so clear), and there is absolutely no smell of chlorine at all. I read 1 case on one of the FAQ pages for RO units in which a woman had a like problem and her litmus strips gave a more accurate result supposedly. I am inclined to say the test kit just will not work for DI water. However, I am not 100% sure of this. Any opinion would be appreciated. <Hmm... is why I don't use test 'kits' for pH - digital probes are more reliable, quick, etc. I'm not color blind but I also just can't tell subtle changes in purple to get an accurate pH reading.> Thank You, Joseph <Cheers, J -- >

Re: Hair Algae (time to check that chemical cartridge) I tested the output from my r/o unit and the phosphate reading was 0.2 which is the same reading I'm getting out of my tank and the tap. I suspect the test kit and am buying another tonight to verify. Question is will the Euro-Reef remove phosphates from the water? I just installed it and I'm getting real good production from this skimmer. Should I reduce the photo-period? Will this hurt anything? I've already used a phosphate sponge! David <If the test kit is correct, then your RO needs help or a DI unit to follow. Your skimmer will remove dissolved organics, but likely not phosphates. Water changes, water changes, water changes (with phosphate free water). Leave all as is except possibly source water, nutrient export with water changes. Once this is under control the hair algae is history. Best of luck! Craig>

RO/DI Unit Filter Interchange Excellent resource for the aquarium enthusiast! <I speak for the crew in thanking you!> Just a quick question about RO/DI systems. I have a Kent Marine Maxxima Hi-S 35 RO/DI unit. I need to replace the sediment filter, carbon filter, resin cartridge, and membrane in my unit. I've heard positives comments about the SpectraPure systems. So I'm considering replacing those 4 filtering components with the SpectraPure brand. Will SpectraPure fit in my unit and is this a good idea? Thanks for the assistance, Edmond <The only question would be the membrane, but these cartridges, filters etc. are all fairly standard as are most RO housings/membranes. Just ask SpectraPure or where ever you are purchasing replacements, they should be able to help. Make sure you match the flow restrictor with the membrane. Craig>

Rechargeable De-Ionizers I just purchased a Kent Deion 200R, to replace the tap water filter that I have been using. I bought this unit because they state that the media can be regenerated. However, they don't tell how! You have to use Muriatic acid, and lye! Sounds dangerous to me. <Depends on your abilities and of course, desire to do so. You sound like an RO/DI candidate to me.> So, my question is, should I just send the unit back, or do you know of a business (Culligan?) that would regenerate this stuff for me. <You might check SpectraPure or even Kent. There are folks on the WetWebForums that have done this, perhaps check there.> Right now I feel like I have just paid 200 dollars for a large version of the tap water filter that I have been using. <More or less that's what you did. It sounds like you should return the unit before you use it and research a good RO unit for your water conditions, perhaps with a DI unit following the RO to remove any additional elements (silicates, etc.).> I probably could do the process of regenerating the media myself, but what do I do with the waste? <Call your county land fill and see if they have a facility for Muriatic acid, lye, etc.> I don't think that I want to put acid into my septic, and I don't think that I want to dump it down the curb, either. <Thank you for being a good citizen! The landfill or county/city will have a facility for this waste.> Thanks again for a great web site, I have used huge amounts of information from your FAQ's. Mike <Thanks Mike, hope this helps! Craig>

Choosing RO/DI - Chlorine vs. Chloramine Hello & Good Day, Everyday reader of your Daily FAQ. I don't really have a question per se, just wanting to pass along some information for people researching the various RO or RO/DI units for purchase. <Okay> Once you've decided on the Make/Model of the unit for you and your fishes and prior to placing the order, call your local Public Works and ask a simple question; Are you using Chlorine or Chloramines for water purification? <Almost all United States municipalities use chloramine> Knowing the answer, and passing this information along to your vendor of choice will ensure you get the proper Carbon Filtering Media. Case in Point - I purchased a 4-Stage RO/DI unit from Aquatic Reefs back in February. Not knowing the answer to the Chlorine/Chloramine question, not knowing there was a difference and not being told beforehand of the importance of the difference I placed my order. Unit arrived and I, excited as a kid at Christmas hooked it up and proceeded to make RO/DI unit water for my tank. Fast-forward to Apr 16th. RO/DI water now measures 45+ TDS. I think to myself -Wow- I've only put approx 125gals through this rig and I already need to replace a filter. So I call Aquatic Reefs. Troubleshooting the now high output and short lifespan of the filtering media led to the realization that my local Public Works is using Chloramine for purification. My original setup was shipped with Filter Media for stripping out Chlorine. The Chloramine has basically 'cooked' the Filter Media, greatly reducing its lifespan. So, in closing, take the extra few minutes to research if you'll need the Filter Media for stripping Chlorine or for stripping Chloramine. Then, be sure to pass the info along to the vendor. I hope this little bit of info is able to help someone out. I'd also like to do a quick shout-out to John at Aquatic Reef Systems. Both he and the company continue to earn High Marks! Many Thanks, Scott <Thank you for sending this along. Bob Fenner>

Water Pressure Issues with New RO/DI Unit Hey folks, I purchased a Coralife 50 GPD RO/DI unit yesterday and am wondering about the pressure of water that enters it. I've hooked up the unit to my No Spill 50 foot water tube which is attached to the faucet in the garage.. I'm finding that the amount of purified water exiting is very little. To quantify it, it's like leaving a faucet open slightly. I'm not sure if it's because I've hooked it up to the No Spill, or is it the water pressure (which seems very strong when I use my garden hose!). The instructions also mentioned that low water temperature can reduce flow. Any thoughts? <Mmm... there's bound to be some pressure loss due to head pressure/resistance here... but not much... You could (while you're about) try measuring the actual production per unit time (with a container of known volume, time piece...). Likely you're getting about what the unit is made for.... about two gallons an hour... Bob Fenner>

Re: RO/DI volume testing Thanks Bob, I'm going to try the unit straight from the faucet and see if it makes a difference! Nilesh <Real good. Bob Fenner>

Ro/di I am installing a new ro/di unit! And I am going to use it for metal plating, so I am going to be using a 40 gallon storage tank! I have been searching everywhere to find the answer to my question, and I have yet to find it, so hopefully you can help me out. If the ro/di unit has to have 35 PSI to operate correctly, then does this mean that I could mount my ro/di unit lower then the tank for easy filter changes, or will the unit have to be higher then the tank in order for gravity to flow the water into the tank, and the auto shut off work properly? <The auto-shut off isn't important as the pressure on the supply side is/will be higher... I would definitely install good shut-off valves (they sell these at Lowe's and Home Depot made of brass for reasonable) ahead and after the unit to facilitate taking it apart> I have heard that these units create a lot of waste water, about 4 to 1. <This is about right... but in actuality... considering the amount of water folks toss on their lawns, landscape, leaks down the toilet... this is miniscule (not just IMO, reality) esp. considering the pollution, time and trouble to go "buy bottle water at the store"> Could the water that is normally sent to the drain be rerouted back to filter through the system, or is the something in the water that will never be removed. Thanks, Wes <I recycle ours to a my garden and have used such water for my fish ponds over many years... this water is barely more solute-laden... about 25% more per... at a flush rate of 4:1... Be chatting, Bob Fenner>

The Strangest Question That You Will Ever Have Concerning RO filters Bob et. al., Here is an exceptionally strange question, I have an RO filter that I had sitting on the floor in my basement beside a drain (like an idiot I never mounted it). To make a long story short, the sewer line got backed up, black water (nothing gross or floating in it) came out of the drain and partially submersed the RO unit. Since these units are have water tight seals, is it safe to say that it is still safe to use and that there should be no risk of contamination by bacteria? <I would think there would be little risk. As a precaution, I would flush out the unit, disposing of all the water and perhaps change the prefilters.> I cleaned the floor with bleach, and heavily flushed the outside of the unit with running water. I guess in a worst case scenario, I could run a UV on the fresh water for a couple of days before use. <You could do that, if you have an extra unit laying around, preferably not in sewage, too.> Let me know what you think. As always, thanks, Tom <Have a nice day! -Steven Pro>

Leaking solenoid Hello all, << Looks like everyone else passed on this. >> I've got a quick question about my RO filter. I have a Kent Marine Maxxima set up for my top off. The maxima is run to my sump with a float valve at the sump. The solenoid is leaking from the middle. The filter is about 5 years old and I seem to remember this happening once before. I'm not sure what I did then, probably just tightened the screws and watched it for a while. Before I did that again I thought it might be a good idea to find out the expected life of the solenoid and if they tend to leak like this. << I would think the life is several years. >> Any thoughts, experience with this? Thanks for your help and your great site! << Sorry we can't be of more assistance. I'd feel bad recommending any action other than contacting the manufacture and telling them the scenario. >> Larry << Blundell >> <I'd replace this solenoid outright. RMF>

- Deionization for Chemophobics - Dear Sir or Madam: I am looking or a water purification system for a 75-gallon reef aquarium. I like the fact that deionization (DI) units are less wasteful of water but I do not want to deal with the dangerous chemicals involved with recharging DI units. I plan to simply replace the resins when they are depleted. (1) For my situation, which is more advantageous: mixed-bed systems or separate KATI/ANI-type systems? <Think perhaps this is six of one, half a dozen of the other as they say... either system would provide filtered water. Individual cartridges of single resin types will last longer than a single cartridge of mixed resin.> (2) What type of prefiltration is required for DI units? <I would use both a particulate filter as well as a carbon filter - much like a two-stage RO unit without the RO. These prefilters will extend the life of the resin cartridges.> Thanks very much. Regards, Paul. <Cheers, J -- >

RO and DI unit malfunction? I have just purchased a new 100GPD RO Filter for my discus, it is a six stage Reverse Osmosis & DI Filter. The problem that I have, is it is not producing soft water, all readings are high, I might as well use my tap water. <...?> I ran it for 10 hours before testing the water, and I have tested the water from different stages to see if it is a certain section that is not working correctly. I have now been advised from the supplier to rock it from side to side to remove any air trapped as this may also cause it to not clean the water correctly, but I can't see that that would make such a difference, can you help. Thanks Simon <Something is awry here... may well be that the unit is still not "broken in"... I would give it another few days, flush, throw away the water... and keep testing. In the meanwhile, get out the directions for install and assure yourself you've connected the components correctly. Bob Fenner>

Mixed-Bed versus Rechargeable Deionization 1/11/05 I have two questions about deionization and determining what purification system is appropriate for my tap water. (1) If rechargeability is not a factor, wouldn't mixed-bed deionization be more advantageous due to its ability to produce purer water? <not necessarily true (usually not in fact). It depends wholly on the resin, and there are many kinds to be had. generally the rechargeable ones are better quality than the disposable hobby use satchels> A representative of Kent Marine stated that a mixed bed deionizer will produce water with 18-megaohm resistivity compared to rechargeable deionizers that produce water with only 2-megaohm resistivity. <perhaps true of some low grade resin he was comparing to for marketing purposes. I assure you this is not the case for all others or even most rechargeables> I notice that SpectraPure uses mixed-bed resins in its "Ultimate" DI system that is also capable of producing water with 18-megaohm resistivity. <its indeed more profitable to keep selling disposable resin rather than rechargeable one time only ;)) Many chemophobics, such as myself, shy away from the caustic chemicals used to recharge resins and would simply replace depleted resins in any case. <Yikes! What a waste of resources! And the recharge chemicals mix to form inert (literally drinkable as demonstrated by chem. lab professionals with carefully measured molar concentrations). You are off the mark here my friend... wasting is not conscientious, re-using is IMO> (2) Where can I take my tap water to be tested to determine if prefiltration & deionization alone is sufficient? <many (water) testing labs online... do a Google search for one that appeals to you (price. service, etc). Maybe ask your local water authority for their official analysis> I'd like to forego wasteful reverse osmosis and use prefiltration with deionization if the quality of my tap water is good enough. I live in Colorado and am deeply suspicious of my "Rocky Mountain spring water." Don't ask me about Coors beer--I've smelled the water at the brewery. Regards, Paul. <have no fear of the two column deionizers my friend... really efficient and environmentally friendly use/re-use. Anthony>

Googling for Dow RO membrane info. Thank you for your assistance in the past. Can someone tell me what a Dow applied (tw30-1812-100) RO membrane is? Is it a TFC or CA or neither? Will this work for well water not having chlorine? Chris Drialo <Uhh, place the term "Dow applied (tw30-1812-100) RO membrane" in your search tool (I did in Google) and read on! Bob Fenner>

Ruggedness of DI cartridge As I usually do, in trying to better my 55 gallon SW set-up, I may have caused a problem. I just purchased a Kent Maxima Hi-S 60gpd RO/DI unit to help me deal with very "fertile" source water. The directions say for the first use to remove the DI cartridge for the first two hours of operation and then re-install it. I got excited last night when hooking it up and forgot to do this. The kicker is, the pressure from the unit caused my faucet to start to leak at the fittings 20 minutes into this initial set-up run so I had to stop it there. I stopped it because I live just north of Philadelphia and was in the middle of getting over a foot of snow and am sure it would have taken a few months of my fish budget for an emergency visit from a plumber! Then this morning, 11 hours later it hits me that I never removed the DI cartridge and that the cartridge sat for that time in the initial water that came through the system. I ran to my basement and removed the cartridge and let it drip dry but am now unclear what to do. <Resume the break-in period as if you were just starting> Do you think I ruined the cartridge? <No> I don't think the color of the cartridge changed but then if there was some type of chemical present in the membrane, it could have discolored the whole thing. Do you know the rationale for the removal of the DI as this would help decide if I need a new one? Thanks, Amy <The initial water from the rest of the unit has chemicals that are not easily "treated" by the deionization part... no big deal though. Bob Fenner>

- Filtration Options - I've got an extra R.O. filter setup (3-10 in. canisters + R.O. membrane). I was wondering whether I could use the three canister filters (i.e., bypass the R.O. membrane) and place them in the main pump return flow line in order to occasionally take advantage of micron-level filtration? Thanks. <I would not do this unless you have an unlimited budget for replacing the filters. You'll find that placing them in the main return path will reduce your flow rate and clog the filters very quickly. Cheers, J -- >

Re: Kati/Ani units Hello again- With the Kati/Ani units....what kind of business would I purchase the chemicals needed for recharging? <I get them at the hardware store and the grocery store.> Is it something that can be shipped or will I have to find it locally? <Locally is much easier.> My LFS only uses RO/DI and only sells the disposable deionizer cartridges and could not offer any advice. <The acid part is Muriatic acid, commonly sold at hardware stores for etching concrete. The base I use is Lewis Red Devil Lye. It is sold at the local grocery stores as a drain cleaner.> Thanks! Have a nice weekend! Dennis <And you do the same! -Steven Pro>

Kent marine maxima 24 gpd ro/di I know this may be a silly question but here it is I need to replace cartridges have replaced mixed bed resin cartridge but not carbon or TFC membrane. have made at least 3000 gal of water system is at least 3 years old. what cartridge would you replace and in what order would you put them I have lost my directions the system has three canisters with TFC membrane on top 1carbon block prefilter (which does not look dirty) <Do replace it anyway... very important physically and chemically to remove what you can before going further with water> 2 blue jelly looking cartidge.3 mixed bed resin high silicate removal. 1 and 2 came with unit. after looking in pet warehse not sure I installed these correctly. THANKS FOR YOUR HELP. ROCKMAN <Do contact Kent Marine re these units. See the www.WetWebMedia.com site for their URL.... "filter parts" on Kent's site. Bob Fenner>
Re: Kent marine maxima 24 gpd ro/di
Robert, Change the pre filters at least every 6 months. The membrane is usually good for 2-4 years. I attached the instructions for the Maxxima RO/DI unit. If you need more information, please let me know. Thanks, John, Tech Dept. <Thanks mate. Will post to the WWM site. Bob Fenner>

Too much Caulerpa and R/O maintenance Dear Bob, It's Howard again celebrating a year of the joy of reef keeping. As usual I have couple of questions as I strive for perfect conditions and perfect water. Still haven't lost a fish. <Ah! Good for you.> How does one know when a R/O unit needs servicing (as everything else in a system does)? Mine has been in use a year and has probably processed 1000 gallons or so. There is plenty of flow, I'm just wondering if it is getting all the bad stuff out. I don't think my testing ability shows the small concentrations that might cause trouble. <Good question. Most folks I bet just taste a difference in the produced water... or figure it's time. But there are simple water quality tests, like conductivity (some water softening, reverse osmosis units come with a light bulb arrangement... with the light "coming on" as the amount of charged particles in the water passing between its electrodes increases)... You can test for total dissolved solids and more as well...> Is it possible to have too much Caulerpa in a refugium? <Yes... as in when it blocks the light too much for the material below it, or impedes water flow... or removes/bioaccumulates too much nutrient you want to go to livestock photosynthates...> I flow about 200 gallons per hour directly from the show tank to the refugium. The 20 gallon refugium is now totally packed with plant growth and producing lots of amphipods. I figure the more I have the more nutrients will be removed and the more oxygen will be produced. is that right? Or is there a down side to too much? <If you see too much dying below, remove some of the Caulerpa...> God bless America, Howard <Be chatting my friend. Bob Fenner>

Re: Guess what? (tank repair, RO run-in period) Hi Bob, So far, so good. All the fish are fine and the soft corals made it okay. I did lose the feather duster starfish and a hard coral. They sat in buckets for 2 days. I guess that was to long for them? <Yes> I received my RO unit yesterday. I have started it off and will let it run for a few days, before I start using it for the fish. <A few hours is long enough> As soon as I get a chance to prepare the pictures I will let you know. Again, many thanks for your help. It is much appreciated :) Warmest regards, Lucien Cinc <Be chatting. Bob Fenner>

Water prep question I have a saltwater tank which is doing fairly well except for a phosphate problem I am having. I have a 2-stage Kent water RO system which doesn't appear to get the phosphate (or at least enough) out of my water as I prepare it for addition to my aquarium. Is there something I could either add to my RO system to reduce phosphates? Something I can add to my tank? Use distilled water from the store? I don't have any better sources than this. <First, make sure your prefilters are getting changed on their recommended schedule. If you continue to have problems look into add on deionization cartridges.> Thanks for your help, Dave <You are welcome. -Steven Pro>

Leaky plumbing Dear Robert (or Steven), <Anthony Calfo... and now we have a full house... or at least three jokers> Thanks again for all of your previous advice - it has been very helpful. I have now obtained an RO/DI system but have not yet been able to produce any water because there is a leak in one joint that seems to be impossible to fix. I've tightened it as much as possible and then tried sealing it with silicone, but the leak persists. Is it more likely that there's a problem with the unit, or that I'm doing something wrong? Do you have any suggestions? <have you used plumbers (Teflon) tape on the threaded fittings? Really the best solution... silicone is unreliable for sealing threads. Do hope this does the trick... kindly, Anthony> Thanks for any suggestions, Ann

RO/DI Bob, I have two questions regarding RO/DI water purification--currently I have a Kent Marine 50 gpd RO unit in series with the Tap Water Purifier (the latter because I keep discus as well as marine aquariums--perhaps a bit of "overkill" to obtain soft water with low pH). First, is it reasonable to assume that an increase in the rate of color change in the TWP resin would be an accurate indicator that the RO membrane (TFC) should be replaced (as a substitute for laborious testing of RO output water chemistry)? <The membrane and/or the prefilters> Second, does the new membrane require any form of pre-treatment (the limited instructions for the replacement membrane suggest high pressure "rinsing" of the membrane to remove some form of preservative (presumably with dechlorinated water to avoid damaging the membrane) followed by pre-running the unit for 2 hours before use of water product)? Sorry for this somewhat contorted question, but I can't remember what steps I went through for the original set-up approximately 4-5 years ago. <Far better to contact Kent Customer service and have them walk you through their procedures. We should have a link to them on our link page. -Steven Pro> Thanks in advance for your input. Dana>

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