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FAQs on Tap/Source Water Use for Marine Aquariums, Treatment Techniques & Tools

Related Articles: Treating Tap water for Marine Aquarium Use, Water Purification Using Reverse Osmosis,

Related FAQs: Treating Tapwater 1, Treating Tapwater 2, Treating Tapwater 3, & FAQs on New Water Treatment: Rationale/Science, Chemicals (Chlorine, Chloramines, Trihalomethanes...), Filtrants, Testing, Troubleshooting, Products by Manufacturer/Brand, DIY Treatment Chemicals/Tools, & Reverse Osmosis Filtration, Specific GravityWater Purification Using R.O 1. RO/DI 2, RO/DI 3, NitratesWater Changes

Mmm, may be that nothing is called for in using your source water... maybe storing it ahead of use... perhaps dechloramination..., contactor/s.  Maybe RO, DI...

Is a water softener essential?    8/1/17
Hi guys.
I'm back in the hobby after being in for 5 years and out for 5 years.
During my last stint as an amateur aquarist, of all the studying I did on reefkeeping, I never came across anyone mentioning the importance of have a water softener in my home as the first stage before going through a reverse
osmosis device.
<There is no such need;
would only nominally improve the job of the R.O. The R.O. can/will soften water and more>
I had hard water, no water softener and was under the impression all I needed was a good R.O. setup.
<Mmm... is all you need>
I never did have all that great of luck in my 5 years. Oh, I could keep things alive for awhile but never really experienced proper coral growth like I have seen other people have.
<Something else going on>
I am now setting up a new aquarium and have drastically downsized due to the money. I had a 125 with a 30 sump and now have a 20 long with the same for a sump. I got this setup from a very experienced person in the hobby, 30 years reefkeeping with outstanding results. Anyway, she said it's really a must to have a water softener in the home first and then the R.O.
My big dilemma now is my home is not set up with a softener and would be very difficult/expensive to do here due to the layout of the house.
<... a "softener"; as in the typical ion-exchange resin type? Again, as far as I'm aware, this is not necessary, or advised>
Toting R.O. jugs to and from the store I fear will get old in a hurry.
Are there better alternatives for me? Would a particular R.O. unit that you know of eliminate the need for a softener? What do you think?
Thanks, Jason K
<I use a cheapy Home Depot R.O., carbon contactor, tris-membrane... We (S. Cal.) have "liquid rock" source/tap water... 800 plus ppm TDS, pH out of the faucet 8.2 or so... Bob Fenner>

Water types     5/14/13
<Hi Heather>
We have been using purified freshwater
from our LFS that we mix with Instant Ocean salt mix to do water changes with.
<Have you been experiencing issues with this method?>
My question is, what is recommended? Distilled? Purified? What's the difference?
<RODI that comes from a well maintained unit is what is recommended.
Distilled will usually be OK but will cost you a lot more in the long run than say buying your own RODI unit. Purified-I personally wouldn't trust it.
I could pour water through my pillow and call it "purified" haha>
We have used distilled in the past.
Any input would be appreciated! Thanks
<Again distilled can/should work fine but is pricey. -NateG>

qu%estion about my water 11/30/11
<Fix this language-wise and re-send>
ok i have another question....when i first started my tank for saltwater,i
used tap water and i used a product to remove chlorine and other small
stuff from the water...i used a product called prime...at that time i
didn't have a ro/di unit, Now i recently purchased one, but before i use it
i want to purify the old tap water thats in my tank and get it 99%
pure..what is safe to use to do this if i have live rock and fish and clean
up crew in my tank and other things....what can i safely put into my tank
to take all the stuff out of the tap water to get it to 99% pure before i
start using my ro/di unit...
Re: qu%estion about my water 11/30/11

never mind..I'm disabled..i typed it the best i could
<Sorry to realize your travails. B>
question about my water 11/30/11

ok i have another question....when i first started my tank for saltwater, i used tap water and i used a product to remove chlorine and other small stuff from the water...i used a product called prime...at that time i didn't have a ro/di unit, Now i recently purchased one, but before i use it i want to purify the old tap water that's in my tank and get it 99% pure..what is safe to use to do this if i have live rock and fish and clean up crew in my tank and other things....what can i safely put into my tank to take all the stuff out of the tap water to get it to 99% pure before i start using my ro/di unit...
<Nothing to use really. I'd just dilute the present water solutes with the use of the RO. BobF>
Re: question about my water
thanks should i do a 20% water change each week, with the ro/di unit to remove the tap water..
<This is a good percentage to be changing out on such an interval period.
Please read here re: http://www.wetwebmedia.com/water.htm
and the linked files above. B>

Water Preparation, 3/11/09 Hi guys, <Hello> I have a quick question about water preparation. I read on your site that water should be aerated for a while before using it to make salt water. I leave a pump in the fresh water container, which I circulate for at least 24 hours. Then, I pump the water (using same pump) into the salt-water container, which has a heater, another pump and an air stone all running. I add my salt and leave for about 2 weeks (basically until my next water change). Is this acceptable? <Sounds fine to me.> Is there a reason why an air stone is better than a pump? <Not really, just looking for water movement.> Do I need an air stone in both containers? <Not unless you like the bubble and related salt creep.> Thanks so much for all of your help. Jason <Welcome> <Chris> Awesome! Thanks so much! <Welcome> <Chris>

RO/DI vs. Alkaline Water Ionizer 3/7/09 Good morning - thanks in advance for answering my questions... <Welcome in advance, hello Jeff.> Is there any benefit to using Alkaline Water Ionizers instead of RO/DI units? Which would you recommend? <The RO/DI, no benefit to the ionizer.> If I go with a RO/DI for my 75 gallon Reef should I also get a unit with UV? <No reason to, you do not have a need to sterilize the water afterwards.> If RO - what GPD production would you recommend to keep up with top-offs and water changes. <Not much, of course it depends on your tank size and configuration, but the smallest units are more than capable of keeping up with 99% of the home tanks out there.> Is there an under the sink unit that can also serve for drinking water you'd recommend? A Seller or website? <Check out Reefgeek.com. They sell nice units you can add a drinking water kit to for little money.> Again thank you very much! <Welcome.> Regards, Jeff Wagner <Scott V.> RO/DI vs. Alkaline Water Ionizer Oh, a bit more to add I mean to. These water ionizers are not at all the same as RO filters...they alter the water chemistry at best. Many claim they are just "snake water" filters. They in no way purify the water anything like an RO filter. Scott V.

Hand Held TDS Meter 1/6/08 Dear WWM Crew, First let me thank you for the knowledge and unselfish time you donate to aquarist in need. I read this website every day to gain knowledge, the books help too. <Thank you Sue.> I just thought I would pass along some information. For everyone who says they can't afford or don't have a TDS meter. Go to Walgreen's Drug store and located by the Britta Water Filters you will find a hand held TDS Meter for $14.99. It is made by HM Digital and is factory calibrated and adjust for temperature. Armed with this knowledge everyone can afford to have a TDS meter. I know that this hobby is expensive and can strain the pocket book so I wanted to let everyone know about a low cost and accurate solution. Happy Reefing! Sue Marietta, GA <Thank you for sharing this information. It will be passed along! ScottV.>

Purified Water 12/4/08 Hello Crew: <Hello Tom> Great site with a wealth of information! <Thank you.> I am trying to understand what I really need to be sure the water I add to my tank is correct. What I have is: 47 gallon saltwater bow tank 3 fish (pair of clowns & yellow tank) various hermits & snails 2 pieces of candy cane coral 1 frogs spawn coral some purple & some red mushrooms green polyps Yellow polyps To purify my well water I use single cartridge system called "Tap Water Filter" by API. <It works, but gets expensive.> What I would like to know is which system will provide the best water? Some have 1, 2, 3, or 5 different style cartridges and stages. I email one company and asked them a similar question and the answer I received was "this one seems to be our best seller". I was not looking for an answer like that. Anyways I hope you can help. <What you are using now is just a deionization filter. They work great, but get expensive to feed raw tap water to. The media just gets exhausted too quickly for the cost. Look at a 3 stage RO, sediment/carbon/RO or a four stage RO/DI, sediment/carbon/RO/DI. Either will suit your purpose fine, with the RO/DI it adds the deionization stage you are using now at the end. By feeding it water that has already gone through the RO filter first it lasts much longer, much more cost effective per gallon. There is really no functional difference from one brand to another, nearly all use the same universal 10" cartridges. This all assumes your tap water needs any treatment beyond dechlorinating.> Regards, Tom <Have fun, Scott V.> Re: Purified Water Hello Scott: Thank you for the clarification. I knew on of the crew would be able to help. Regards, Tom <Welcome my friend, have a good night. Scott V.>

Tap Water for Reef 8/22/08 Hi all, <Marc> I have a question to do with treating tap water. I have a 75 gallon saltwater tank with some soft corals, and want to add a few LPSs corals. I do a 15% water change every Friday. I was just mixing the water right before adding it to the tank. I use Reef Crystals, and I was using Prime for a conditioner. <I personally would steer away from using any conditioner.> It was going fine for a while, then when I was at my LFS, I mentioned I wasn't getting much coralline algae growth, and I keep the calcium and hardness up where it needs to be. I was told it's cause I use tap water, so I started using RO water. But between weekly changes and top of water, it's been tough to keep making trips to the LFS. <Tap water is not necessarily a bad thing. Were there any test to justify the switch?> If I fill up the buckets, and use Prime, and let them set for the week prior uncovered, should I be all right at that point? <I would skip the Prime and just let it sit for a few days to a week. Do some basic tests on the water to see if it is suitable, most those for a reef tank. Phosphate, nitrate, nitrite, etc.> Or do I really need to add powerheads to the buckets? Also should I use something else to get rid of the chlorine? <The aging will rid the chlorine. I do urge you to actually test the water to see if there is reason to switch. If there is, your own small RO unit will be more economical and easier in the long run. Do also test your magnesium and phosphate levels in your mixed water, these, along with lighting can have an impact on coralline growth.> Thanks for the help, Marc <Welcome, Scott V.>

Re: Tap Water for Reef 8/22/08 Scott, Thanks for the help. <Welcome.> I'm going to test for everything right now, if everything is ok other than the chlorine, I'm just going to continue to use the tap water. If I let it sit for a week, do you think it would be ok without a powerhead? <The chlorine will dissipate, although it will faster with a powerhead. The powerhead will also help in oxygenation and mixing in the salt. Maybe just run it the last day or two of the aging.> Also, how do you feel about Purple Up? <A product not worth using IMO. If your Ca is low, raise it. If your Mg is low, raise it. Adding an "all inclusive" product will eventually lead to disaster.> Thanks again, Marc <Welcome, Scott V.>

Tap Water Treatment -- 12/07/07 Hey Eric what's up? <<Hiya Don!>> I have a tap water question, my tap has 1.0 ppm ammonia, no nitrite or nitrate or phosphate. <<Okay>> If I were to fill a 90 gallon can and throw Amquel + a power head and salt for a week, would all bad stuff dissipate and would it be ok to use for water changes? <<The Amquel+ will remove any Chlorine/Chloramines/Ammonia, and may detoxify other elements, but will not remove 'all bad stuff''¦if present. That said, I see no reason not to give this a try. How your tank responds will answer your question>> I don't have a RO unit and getting tired of carrying buckets. Or anything you can think of'¦would be grateful. <<I do prefer RO/DI for water prep'¦but give your idea a try>> Also my fish that had Crypt are clear and the 22nd will be 6 week protocol to go back into 210 tank. <<Excellent>> Plus I went out and bought a 90 gallon hospital/quarantine tank <<Ahh'¦lots of room!>> Thanks again for all the help; it's been fun even through the rough times. <<Am looking forward to your (good) progress reports. EricR>>

Re: Tap Water Treatment - 12/09/07 Eric, <<Don>> Ok, bad stuff can mean a lot and I thank you for the quick response. <<Indeed'¦and quite welcome>> What exactly bad stuff would I be worried about without getting into all sorts of crazy water chemistry. <<Much of what may be in your tap water can not be tested by you/hobbyists, though you can contact your water company and ask for a written analysis'¦and you might be surprised at what you find (heavy metals, pesticides, etc.). And though these will likely be in miniscule amounts, what is deemed safe for 'us' does not hold true/can still be problematical to your marine system>> I do know Kordon makes a few water conditioner products beside Amquel +. <<But of little to no use to you/your purpose. There are no magic elixirs out there'¦ It is my opinion you and your system will be happier in the long run with some type of filtration unit (RO/DI) to pre-filter your tap water before use. Do let me know if you wish to discuss these further, and/or read here and among the associated links: http://www.wetwebmedia.com/h2opurifiers.htm . EricR>>

R2: Tap Water Treatment - 12/09/07 What about adding things like carbon to premix? <<Can't hurt/will help to prefilter your tap water through carbon'¦but is still no replacement for a good filtration unit>> I'm really not trying to be lazy because I've been traveling for RO water, but my health is on a decline and carrying 12 buckets 2 times a week is rough. <<Mmm, sorry to hear'¦and yes, much agreed. I automated my own system so a 50 gallon water change takes about 15 minutes. A turn of a valve to drain'¦a push of a button to fill'¦fantastic'¦>> I am big into water changes 10-20 %. <<Excellent'¦is the single best thing you can do for your system>> If not, if you know of a great company that has RO unit at reasonable cost send the link please. <<Ah yes'¦check these guys out'¦http://www.thefilterguys.biz/ro_di_systems.htm >> I really don't know much about them. <<Do let me know if I can help with this>> Thanks Again. <<Cheers, Eric Russell>>

R3: Tap Water Treatment - 12/10/07 Eric, <<Don>> Nice RO filter. . $124.00 - OCEAN WAVE SHELL FOUR STAGE 75 GPD REVERSE OSMOSIS SYSTEM... <<A nice unit, agreed...though for $10 more you should consider the five-stage unit with the DI cartridge>> How the heck do you install it? LMAO <<The units are fairly easy/straightforward to install. You can either 'tap in' to a cold water line much as you would to install an ice-maker feed line (make sure you have a valve in-line to shut-off flow when not in use), or, if a faucet is within reach, you can use a faucet adapter to connect the infeed line (adapter may come with the unit, else will have to be purchased separately). You can check with the vendor to be sure, but the unit will likely come with written instructions for installation. Also, I am familiar with this vendor and I know they will do all they can to assist you with the install or to troubleshoot any problems that may arise. EricR>>

Dechlorinators  12/10/05 Hi, <Hello.> I was wondering if using a water conditioner is important when doing a water change on a saltwater tank? I use to use one as a safe guard against chlorine but never really knew if I was wasting my money or not. <Depends on the source water. If you are using tap, then yes a dechlorinator is necessary, if this RODI water, other than aerating it, nothing is necessary.> Thanks, <Welcome.> Scott <Adam J.>

Boiling Water For Aquarium Use 01-01-06 Hi crew.   <Hello> Just a quick question about water treatment.  I have a 38-gallon reef system with various pieces of coral, live rock and crushed coral for substrate.  The system has been running for over 6 months.  Every thing in the tank in thriving including a bunch green hair algae that's been growing on my live rock for a while now.  The algae never really bothered me, as a matter of fact; it kind of made the reef system look better.  But it's getting to the point know where it's beginning to grow very tall and I have to keep trimming it every week.  I've been saving my pennies to buy an RO water filter.  Hopefully that will remedy my algae problem.  My LFS suggested that I boil my tap water and store it.  They stated that boiling tap water works as good as an RO unit.  What do you think?   <That is completely false.  RO units remove organics and heavy metals from the water. Boiling your water will actually concentrate those elements as the water evaporates. A good example would be the ring inside a coffee pot, usually a calcium/lime build up. Boiling your water will do nothing for your algae issue. RO will help, but you will also need to make sure your tank has undetectable nitrates and phosphates to "snuff" out the algae.> Your advise will be greatly appreciated. Elvin -- Milwaukee, WI <Glad to help, Travis>

Dechlorinators etc. Hi, <Hello!> I was wondering about the chemicals used to detoxify tap water. I have a  marine fish/reef tank and I use the chemical such as Amquel to detoxify the chloramines and chlorine for the water I use for changes and topping off. Now I heard these are not good and contain some type of polymers and other bad chemicals, is this correct?   <To my knowledge, dechlorinators do not contain anything harmful. However, you could achieve the same result by aerating the water in a container for a week or more. If you give the water oxygen and turbulence, the bad chlorine and chloramines will dissipate on their own. Dechlorinators don't remove anything from the water...they simply neutralize it. For more information, do a word search containing the word "dechlorinaters" at Wetwebmedia.com For a reef tank you will likely need RO/DI water.> And another question I have is with the bio-balls in my wet/dry filter. Do these cause the nitrates to raise? <Yes> I've heard of people taking the bio-balls out if so what do I use?   <Live rock inside the main display to the tune of 1-2 lbs per gallon and/or continue to use the wet/dry. Just submerge the balls instead of allowing the water to trickle over them. Thank you, Tim <You are most welcome! David Dowless>

Definitive answer on chloramine? As I have learned on your site (along with a multitude of other things...thanks), I have been aging my water in a trash can for about a week before using it for water changes. Because of the chloramine in tap water, I have also been using a product to detoxify it. I know I have read that such products are unnecessary if water is aged for about a week; however, being a novice aquarist with a sponge for a brain I'm reading everything I can. What I have read is: ["1) Chloramine is present in toxic quantities in virtually/actually all city water supplies, 2) It takes a good week or so to "dissipate" by "setting", "aeration", "hopeful wishing", or other such means"...] but also I have read ["chlorine will dissipate in open air but chloramine never will... a chemical bond that must be broken (with a de-Ammoniating product.. most conditioners)"] What is the definitive answer on this? Thanks. --Charlie <All are "so" except the last statement. Chloramine will/does dissipate with exposure to the air, aeration in a week. You can get/use a chlorine/chloramine test kit (colorimetric assay) and check this out for yourself if you'd like. Bob Fenner>

Re: he says...she says...know a good divorce lawyer? (Water Changes) Greetings!   Please settle a dispute before we go to blows.  =) We're planning a water change for next weekend on our 90g reef.  I had planned to go to the store and buy about 15g of purified water and mix it with Instant Ocean and aerate it the night before we do the water change. My husband says to save the money on the purified water...he's saying if we fill up 2 5g buckets of water on Thursday and leave the tops off, that all the impurities and chlorine and garbage will "burn off' in time for the water change.  I've read your faq but haven't seen this argument before.  I guess the other option would be to go to the LFS and buy some of their water?  Any ideas are appreciated.  Can you come out here to California and help?  heh heh <For the most part your hubster is partly right this time. Most everyone can "get as much benefit" as they're going to by pre-mixing and storing their synthetic... made with simple tapwater... by mixing, circulating it for about a week before use. Please see here: http://www.wetwebmedia.com/water4maruse.htm and the linked FAQs (at top, in blue) beyond. Bob Fenner> Have a great weekend...go raiders! mo

Garden hose use Any reason why I should NOT use a new clean garden hose (with the ends cut off) to transfer salt water to my display tank when I do a water change? Thanks, Michael <Some have a "funny" vinyl smell and taste to them when new, but all I've ever seen were labeled as safe for moving water for human consumption, so I don't see a difficulty. Bob Fenner> Garden hose toxicity Thanks Bob! I noticed that most garden hoses have a Calif Prop65 warning that they contain chemicals known to cause cancer in humans.  But I suspect I would have died as a child if that were truly a big issue. Michael <Ha! I suspect I would as well. Also, if one reads, writes on the Internet (long enough), am very sure they will die! Bob Fenner>

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