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FAQs About Water Evaporation, Make-Up H20: Techniques

Related Articles: Marine Water Change, Captive Seawater Quality, General  Marine Maintenance

Related FAQs: Make-up Water 1, Water Changes for Marine Systems 1, Make-up Water: Rationale/Use, Gear, Frequency/Amount, Water Quality/Adjusting, Trouble/shooting, & Top-Off System s, Controllers, Treating Tapwater Marine Water QualityMarine Plumbing


quick sump top-off question   9/24/11
Happy first day of fall to you, Crew.
<And you Dustin>
I'm writing this morning with a quick ATO question. I recently read Josh McMillen's article on the pressure locked sump baffles and loved it. As I'm always looking ahead to the next larger tank/equipment, I really dig the modifiable nature of this project. I'll be using it in my sump (29g for a 40b) to partition off the middle as a refugium. In the first chamber will sit an AquaC Urchin (yours and other reviews just made this choice a no-brainer). After that will be the 'fuge, then the return pump chamber (debating on whether or not to add a few baffles for a place for a bag of carbon, but that's another issue). For an ATO I'm using a Tsunami attached to an Aqua Lifter pump, run through my super-glamorous Rubbermaid
trash can RO reservoir.
Logistically, I'm trying to figure out where the ATO sensor should go. Am
I correct in assuming that it goes in the return pump chamber?
<Better to put in an area where it's a bit more calm really... though it has to be some part that the water level does go up/down...>
Also, what do you think of the Tsunami's as opposed to a regular float switch?
<Mmm, an okay product... make sure you provide a decent pump... Best to not supply systems w/ a largish volume of make-up water... potential for overfilling... >
It's a nice, easy to use device, but due to it allowing a good deal of fluctuation in water level, I'm not sure if it's having a detrimental effect on my SG consistency.
<Not if you're careful re the above>
<Welcome. BobF>

Tap water straight from faucet to aquarium?   4/1/07 HI I use all distilled water for my FOWLR tank, <Careful, some distillers use copper coils.> but recently I took the tops off and switched out for egg crate.  I am experiencing lots of evaporation which is in turn using a lot more of my stored distilled water for water changes.  Can I use un-aged, untreated tap water for my top offs? <I wouldn't. Not only will here be chloramines and heavy metals but unwanted nutrients such as phosphates. AND...depending n where you live a multitude of other nasties, tap is so variable and even when it's to be used it should be aged/treated/aerated.>   My concern of course is chlorine or possibly chloramines but its my understanding in a 75 gallon tank the effects would be so little of adding like 1 gal. that it would not hurt anything? <Yes but the "nasties" mentioned above would add up over time.> I would be nice to be able to get room temp water from the faucet and add it right in.  Thanks. <See above and articles posted on WWM. Adam J.>

Water to use. Tap trtmt 10/03/06 I have a 60 gallon DAS with 65 pounds live rock and 110 pounds live sand. Currently I only have a hammer coral and xenia and some cleaner crews going. The tank has been set up for 2 months. I am having some evaporation. I understand that I need to add some water that does not have salt in it since the salt does not evaporate. My question is Do I have to get RO water or DI water or can I filter my own water through an inline filter that I can get at Lowes or home depot to remove the chlorine and such? <You do need to use RO or DI. I suggest using a system designed for aquarium use. The drinking water systems at the big box stores (or anywhere for the most part) are not a good idea for use in a tank with invertebrates.> Thanks a million, <Very welcome and best of luck - Emerson> Mark

Kalkwasser And Top-Off Systems - 08/08/05 I have a 29 gallon reef with a 175w metal halide and two T5 actinics with a Remora hang-on skimmer and running some Rowaphos in an Aquaclear filter.  My inhabitants are mostly softies, xenia, star, zoos, Ricordea and also some SPS (Stylos, Montipora, stag frag).  I will be upgrading to a 55 gallon corner tank soon. <<neat>> I plan to build a remote sump system in my garage and want to make a dependable freshwater top off system using a 7 gallon container (salt bucket size) filled with R/O water and using a float switch and an Aqualift pump (2-3 gallons per hour). <<ok>>   I have been told I can use Kalk solution in this setup. <<yes>> Basically mix Kalk and 5 gallons of R/O then after it settles, siphon off the water to fill my evap makeup reservoir.  I was told I could run this setup 24 hours a day since it just adds water in small amounts many times a day, just refilling with this Kalk solution once a week or so. <<As needed, yes.>> The next better option may be to use a Kalk reactor??    <<Matter of preference...the reactor is less troublesome in my opinion (easier/quicker to service). Can you help me be smarter about these two setups and how they would work for my tank? Any suggestions or "counseling" is really appreciated. :) <<Well Bob, either would/will work fine.  Many, many folks do what you propose (or similar) with mixing up Kalkwasser solution and using it to top up your tank evaporation.  This is one of the easier/more simple methods for dosing Kalk (aside from Anthony Calfo's slurry method).  My preference is to use a Kalk reactor, but these are more difficult to build/expensive to purchase.  Both methods utilize your makeup reservoir and pump (water is pumped through the reactor) to dose the Kalk, the reactor just does the "mixing" for you.  But don't fret, you don't "need" a reactor, you're original plan sounds fine.  Have a look at our FAQs on water top-off systems: http://www.wetwebmedia.com/h20makeupfaqs.htm>> Thanks Bob <<Regards, EricR>>

DI water for top off Hello, I have a Kent DI unit that is attached to a float in my sump that automatically replenishes my evaporation water, now this water is not buffered and I suspect it is one reason for my PH staying in the 8.0 to 8.15 range (also run a calcium reactor). I was trying to think of a way to buffer the water without changing my current set up and had a "crazy" idea that I would like to get your opinion on. I was thinking of adding another stage to the DI unit at the end before going to my sump, fill the canister with some media that would dissolve raising the buffer and PH, if I filled the canister with the same media used in my reactor would this work? I know the water is acidic coming from my well and the DI makes it no better so my thoughts are the media would dissolve (just like in my reactor) and therefore buffer my top-off water. Thanks for your time, all comments are appreciated. Thanks <Hello, I think your idea might work but I probably wouldn't go that route.  I would get a aqua doser from Kent or some other similar doser and just dose at night with Kalkwasser.  It will be more easily controlled than trying to use aragonite to buffer the water from your D.I. unit.  Good Luck. MikeB.>

- Temperature Adjustments in Top-off Water - Hi Crew, Sorry about this question and the answer maybe obvious to some of your readers however, I am going to as since you can never ask a dumb question. <The only dumb questions are the ones that remain unasked.> I like others am losing water to evaporation in my 200 ltr Marine Tank. To Top this off, Can I fill up a 10 liter container with fresh water straight from the tap, add some de-chlorinator and add some boiling water to bring the temperature up, then simply add it to the tank. <You could, but better to let the water sit... bring the temperature up with an aquarium heater. The possibility exists that the heat of the boiling water would either be too much or break down the dechlorinator.> I noticed that my protein skimmer, loves this and starts pumping out what appears to be water (unless the fresh water has a lot of proteins in it). <More likely is the dechlorinator.> So I figure something is just not quite right here. I would be grateful for your thoughts on this. Cheers AO. <Cheers, J -- >

- Top off During Vacation - I'll be going out of town for a little bit this summer and I'm leaving a relative in charge of my tank. <Hooo boy!> I'm not so much worried about feeding but more so about evaporation and the specific gravity. <Yes... is perhaps one of the more difficult things to have non-experienced folks maintain while out of town. I've been burned this way more than once.> I'm preparing about 15 gallons of water, and am going to make it easy on my caretaker to just top-off the tank to a designated level every week. <Yes... easy to just put a piece of tape on the outside of the tank or sump to show the desired water level.> If my Specific Gravity is at 1.0235 what should the specific gravity of the water to be added be? <0.000 - You want top off water to be freshwater.> I'm thinking around 1.020 range, as last time I had a spike in my specific gravity. <Not a good idea... your tank salinity will slowly creep upwards if topped off with saltwater.> Suggestions? <Freshwater will be fine... just add a small amount every day or perhaps every other day.> Thank you very much for your time. -David "A man who goes to sea without a reason would go to hell for a holiday." <Cheers, J -- >

Hello and Thanks again...quick question 5/31/04 I have included some photos this time to aid you in visualizing the tank  setup so you can help me out.....Thanks for taking the time...First question is about auto top off....what is the correct way to do it on a 120 gal. reef and what is the best equipment to do it with...ro/di Tunze Osmolator etc? ro/di to storage container with float valve? Then Tunze Osmolator hooked to storage tank and display or sump to activate auto top off? <I am not a big fan of auto top off devices because of the risk of failure.  I would suggest that whatever delivery method you choose that the water be drawn from a reservoir.  This will limit the amount of water that can run into your system at once if the device sticks open.> Also the second question is about pump sizing...I have included the pictures for this purpose.... <Your pic was not attached, but I will try to do my best without it.> The return pumps... I will have 2...one for each side of the tank and I am looking for 1500 to 1700 gph total between both of them... <Good plan.  Having two pumps offers a nice measure of safety if one fails.> From each pump the return line runs up through the custom overflow box with dual 1 1/2 Durso standpipes (o.d) into a "T" connector one output runs along the upper portion of the tank to the top right rear corner with a ball valve attached to regulate flow....the other part of the t runs down the outside of the overflow box and to the front bottom corner ...second return pump repeats the same sequence on the left side of the tank. (see attached photos) <I think I understand your description.  Be sure that you place at least one outlet very near the surface of the water.  This outlet will allow air to enter and prevent siphoning back to your sump if the pump stops.> taking into consideration the return line layout (3/4 " pvc) what pump would reliably give me the output for that side of the tank to reach a combined total of 1500 to 1700 gph.. <Many submersible or external pumps will fit the bill.  Look for models in the 1000 gph range each to get your desired flow after frictional and head losses.  I am a big fan of Iwaki and GRI for external pumps and Mag-drive and the new Quiet-One for submersibles.> and also how can I stop the tank from draining if the pump fails being that two outputs will be in each front lower corner?  Thank you for your time... <See my comments above about placing outlets near the surface.  Best Regards.  Adam>

- Chemical Filtration & Makeup Water Heating - I have done some reading about the two products Chemi-pure and Phos-Zorb.  They sound like really good products for my reef tank.  What I would like to do is place these two in a hang off the side filtration system will they work that way? <Yes.> I have several dual chambered hang off side systems lying around from my cichlid days.  Not worried about unsightliness because I bought a tall tank and stacked the live rock all the way up to the water line.  It gave the tank an interesting effect.  I have fish living in an almost apartment style from top to bottom. I installed mirrors on the wall in back of the tank with dim lights to see what goes on back there.  A lot let me tell you. It's a regular dance club. Complete with bass players and a sand bar.  I also have several corals put on the rocks I took the time to make sure all are secure ( I built little PVC holders custom made for each coral to keep them off of the rocks and out far enough  to let them fully expand and grow.  Very ugly at first but now all are overgrown with coralline algae) I put light lovers at the top, deeper water ones down at the bottom, aggressive corals with plenty of room.  I also have a few anemones in and around the rocks.  Very aggressive skimming a Sea-Clone 100 (I know not the best skimmer, but I made a few modifications on the air inlet valve and now I get a whole lot of brown goo in the cup about every other day.)  The reason I wanted to know about these two products is I use a very simple filtration system.  A gravity flow of water from the bottom of the tank into a modified plastic bucket filled with floss and activated charcoal and a big power head to pump it back up into the tank. I guess really the power head helps suck the water through the filter so it is more of a gravity assisted filter.  It has worked well for over three years, Sea-Clone 8 months,  but I want to do the best I can for my conversation piece (aquarium).    Also I keep 33 gallons of salt water for my every two week ritual of water changes, I only aerate it.  I have been reading that some people heat their water in the container. <I'd be one of those people.> I always thought this to be a grey area. <Not in my mind.> Should I keep all 33 gallons at 78F or heat it just before I use it? <Yes... or at least heat it up a day or two before you use it - adding water that is not temperature matched to the tank can be a source of stress for your animals.> Thanks ahead of time, Craig <Cheers, J -- >

- Top Off System - Hey guys, I have a 75 gallon tank that evaporates about 1 gallon per day (very aggravating). <Have had my own set of aggravating top-off problems.> Several months ago I set up a 5 gallon bucket as a top-off reservoir.  I put a powerhead in the bottom and ran a hose into my sump.  The powerhead plugs into an outlet that I have wired to a switch, when I flip the switch, powerhead comes on.  Beats having to pour water in everyday.  However, I was still having to fill my top-off bucket every four to five days, so, tonight I went to the store and purchased a 30 gallon trash can.  I figured that should hold me for at least 1 month.  I kept the set up the same, however, after topping off my tank I returned one hour later to find 30 gallons of water on the floor. <Fun, not.> It seem that once I turn the power off to the powerhead there is still a siphon. <Yep.> I cut a large hole that would "catch air" breaking the siphon, but it did not work.  How can I set this up for water to only come through when the powerhead is on, not thereafter as well. <Not so easy with a trashcan full of water - even if you were to plumb a through-hull, you'd still have the weight of 30 gallons of water wanting to empty out through the powerhead. If I were you, I'd take a look at the peristaltic pumps available through Innovative Aquatics in Connecticut: http://www.innovativeaquatics.com/ - I purchased one of these units several weeks ago and have been quite satisfied at the results. The unit I chose has a float switch which turns the pump on, and then you can select a rate at which to pump water. The nature of the peristaltic pump does not give way to siphons. The fact that this pump eliminated my top-off problems [unreliable float valve] made it worth every penny.> Thanks so much! <Cheers, J -- >

- Buffering Top-off - <Good morning, JasonC here...> I was just told by another experienced reefer, that he does not buffer his top off water in a reef tank... using ro/di top off. He is using a calcium reactor. Are calcium reactors typically automated to the extent that they make up for the acidic top off. <No... calcium reactors are fed from the tank and return to the tank, and essentially a zero-gain when it comes to water additions. Likewise the effluent from a calcium reactor is about pH 6.7 so not buffering the top-off is not a good plan.> I am planning my set up, and I would like to plan a vacation so that the wife does not yell at me for not wanting to do anything but pet fishing. Therefore I am trying to plan my top off H20 for a 10 day excursion. I have dripped Kalk before, but at the 3 gallons a day I will most likely evaporate, I do not have anyone that I could trust to secure my system in my absence. <Time to find them... look perhaps for a tank maintenance company.> Any thoughts would be appreciated. <You might also consider filling a garbage can with top-off water and using a float valve to do the work in your absence. Test this before you leave town, but should work. Cheers, J -- >

- Re: Buffering Top-off - So I suppose I treat/buffer the garbage can water, then I still drip Kalk or make a Kalk slurry. <Yes.> Does a Kalk reactor provide a better auto system. <I think that is how Kalkwasser reactors are intended to be used, but given that you evaporate three gallons a day, that's a lot of Kalkwasser to be adding. I would stick with normal top-off and then supplement that, but not use a Kalkwasser reactor exclusively. Cheers, J -- >

Top off system Hi All, Thanks for the help in the past.  I owe all my knowledge and successes gained in this hobby to Bob, Anthony, Craig and rest of the Crew! <Glad we could help my friend!> Anyway, on the topic of RO make up water to replace evaporation in my reef, I understand the benefit of buffering it before use - since the PH is very low (around 6). <And Alk too!> My concern is this: I am using a daily 2-part buffering system that maintains my Ca and Alk param.s perfectly.  My top up is dripped in 24/7 using an automated system with a float switch, so there are no sudden PH swings (I understand the risk of using such systems, but I'm willing to accept it because it makes my life a whole lot easier and the hobby much more enjoyable). <If this works well for your system then I would stick with it. You *are* dosing both parts A and B separately, (as per the label) *right*?  Likely using the buffer part *alone* as the drip to "stabilize" pH? This is okay.> In my case, is the risk even that severe anyway?  Am I correct to say that all 4 gallons of RO @ 6PH dumped in at once would drop the PH in 90gallon system @8.2 down to about 8.1. If this is about right, it doesn't sound too critical to me. <If one considers pH only. Not too much to worry! What happens to your temp, salinity, alkalinity, calcium, etc. when you dump 4 or 5 gallons of cold RO water into your system?  The effect is dependent on overall volume, (and where it's released) which is why I sent you to the DIY pages to size your top off volume to your overall volume in case such an event were to take place. Consider all water param.s in this case to be safe!>   I calculated this as follows: 5% Total Vol. 6PH 95% Total Vol. 8.2 PH 50/50 would bring PH down to about 7.1 or for calculation purposes, we'll use 1 full point. Divide by 10 to get 5% and we get .1 - is this a good enough calculation? I personally see that in my case buffering my top up a moot issue.  I agree that in the event all my top-up gets dumped in at once (i.e. during a failure) the impact would be less with buffered water, but other than that is it really required?  Doing so will just make the effort of maintaining consistent and balanced Ca/dKH more difficult - not to mention the added costs and time of doing so since my tank evaporates about a gallon a day. Thoughts always appreciated! Steve <Your system will likely evaporate more than a gallon per day in the summer months, do consider using Kalkwasser dripped to maintain calcium/pH and periodic additions of buffer/carbonate alkalinity supplements as opposed to two part additives in larger systems like a 90....very expensive unless ease of use is paramount, in which case, continue on mate. At any rate, 4-5 gallons of cold, unbuffered water into 90 gallons could/would be problematic in proportion to how fast (and where) it is released. Through a float valve into a sump, overall, not much to worry about....unless it floods. Even then, in view of how much water I can put on the floor, 4-5 gallons is a slap on the wrist! No worries!  Craig>

Buffering RO for Top Off Dear crew: If I would like to hook up a RO unit through a solenoid and a float switch to replace my evaporated water, do I need to add buffer to the new RO water before I add into the sump?? Or can I even just hook up the water line without the RO?? Will that be ok? Eric <Hi Eric,  Because RO removes most to all mineral content, the resulting product is acidic, in the pH 6 range. This water should be reconstituted or buffered to raise pH and supplement the lost carbonates in reef systems, unless it will be used to mix Kalkwasser (then use it as is).  I recommend running the RO into a secondary container, like a Rubbermaid tub or trash can and running a solenoid or float switch for a pump or gravity feed into your sump. There are several good plans for these on the web, search for them at WetWebMedia.Com under top off systems and DIY. The best system I have seen, used a float valve, gravity fed with a limited supply, (sized to the system) so a failure wouldn't have overwhelmingly negative impact.  A solenoid or float valve failure will then only introduce so much top off water. Many people periodically add buffered water to supplement carbonates but mainly top off by dripping  Kalkwasser which you don't want to buffer. Many options available including several commercially available systems.  Check out some of our sponsors for these. Yours, Craig>  

Evaporation top off systems Help Please! I have a 125 reef tank with ecosystem filter.  I evaporate a little over 1 gallon per day due to cooling fans.  A local fish store recommended a cheap way to add evaporated water would be to use a vacuum pump.  The vacuum pump would take water from a 10 gallon tank and with a timer, pump water into the filter.  I plan to use a power head to circulate and aerate the 10 gallon reservoir tank.  Does this sound like a good idea? <I would go to this page and look at several ideas... http://www.ozreef.org/diy/index.html#TOP_UP > Can I add my additives to the 10 gallon reservoir tank?  Steve. <Some can be dosed together and some not. Depends on which additives you use. Follow label, do not mix carbonate Alk/buffer and calcium/mag/strontium/Kalkwasser in any case.  Take care that your top off can't overflow your system or overdose additives/FW.  Craig>

Auto Top-Offs -Jason, <Good evening...> I've reviewed as much info as I could find on your site regarding auto top offs and my primary concern is the failure of a valve or switch. <I think perhaps I wasn't entirely clear - I was trying to convince you into a different 'way' to change the water; not in small, constant amounts, but in one fell-swoop - more akin to using buckets, but also incorporating your desire to use these tanks. I do not propose you go full-blown auto top-off, but rather crank the valves by hand.> How reliable are the Kent float valves. <They work.> What's the most reliable switch? I like the simplicity of a float valve but it would be difficult to build in redundancy as one could by using multiple switches. <Again... these items add unnecessary complication - consider just putting a hand valve where you might use a float switch.> Regards, George <Cheers, J -- >

- Re: Semi-Auto Top off - Jason, <Good morning.> You were clear as far as your water change recommendation, thanks. <Oh good - sometime I worry that I prattle on too much.> Seems like I read a reply from one of the crew that said that some commercial breeders and public aquariums use a slow, constant exchange method and that it was superior, but I am convinced that I need to stick with the simpler method you suggest. Likewise, I thought that small, frequent automatic top off amounts were better than introducing larger amounts of fresh water to the system less frequently, but I am paranoid about failed float valves or float switches. <Don't blame you there...> Think I'll stick with a manual top off system as well. Can't wait to get the nuts and bolts issues out of the way soon and start talking about animals. <Sounds good.> Many thanks, George <Cheers, J -- >

Top Offs... Thanks for all of your answers! <Glad to be of service! Scott F. with you again!> Is it OK if I keep forwarding the previous message so that you will remember my set-up? <It's fine with me, but we usually can't print the previous messages in the interest of space..> One more question about the refugium. <sure!> If I grow macro-algae within 16 inches from the surface what sort of lighting should I use? Coralife makes some 10 watt 50/50 that screw into a normal 110V light bulb socket. If these would work well in this application, how many should I use?  If this was your refugium what would you use? <I use compact fluorescents. I think that 2- 32 watt, or 2- 65 watt bulbs would be just fine> Last question for today. I use RO water for everything, and like I stated before it tested out at 4ppm dissolved solids (quite well I was told).  Could there still be phosphates in this water that is fueling Cyano algae? <Could be. The dissolved solids could be just about anything, unfortunately. It does not take too much phosphate to generate nuisance algae growth, so it is possible. If the membranes on the RO unit need replacing, it's possible that undesirables are getting through...check them! Also, use of good chemical filtration media, such as Poly Filter, will help remove excess phosphate and other impurities from the water once it's in your system...> Also what is your opinion on automatic top-up devices (float devices) inside a sump? <Honestly, they scare the hell out of me! Sure, they work, and there are many well-constructed systems out there. But I have had a few friends who have experienced outright catastrophes from malfunctioning units over the years. I am of the old-fashioned, labor-intensive, haul-the-water-in-a-bucket school of water top off! If you are a DIYer, check out the great site Ozreef for some better plans> Will this cause a problem, seeing that the water is not aerated or buffered? <Frankly, I think that it's better to prep the water before adding it to the tank or auto-top-off system> If I do add water via this method is it OK to just compensate with buffer to keep ph and alkalinity up?        <I'd treat it like any other source water that you'd use in the tank. Hope this helps! Regards, Scott F>

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