How to stop evaporation

cubsfan7667

New member
Hi i have a 40 gal breeder with a 15 gal sump.

My problem is that every about 4 days i have to add water to my sump or else it will run dry.

Does anyone know why this is happening or how i could stop it.

Im pretty sure its because of evaporation.

Let me kno wat you think

TY.
 
I would be interested to know how, other than sealing the system from the atmosphere, you plan to stop water from evaporating?
 
Just part of the game, replacing evaporated water. It shows in the return section of your sump since it has the lowest water level. Mine evaporates about a gallon a day. I just have an auto top off float valve hooked to a pump that replenishes it as it evaporates. My top off supply tank hold 5 gallons, so I end up refilling it every 4-5 days or so.

One way to reduce evaporation would be to put a glass top on all parts of your system, but if you have any powerful lights, that will just result in heating up your water too much. The evaporation is what cools your tank.
 
It's just something that must be down. Putting a lid over the tank and the sump helps but I have to add at least a gallon or two every day inorder to keep levels normal.
 
well firstly, you should be topping off every day, if not at the very minimum every other day. 4 days between top offs is quite a long time and with that much evap, you run the risk of shocking something do to no consistent water balance. Your salt level will be going up and down and whatnot all the time.

Like said above, the only way to stop evap would be to completely seal the system, at which point you've got other (and much worse) problems, such as no gas exchange (your pH would suffer badly) and no heat release.

Every tank has evap. Tanks with sumps have like double the amount because more water is falling over air, or however you want to describe it...basically more surface agitation.

The only thing IMO you should change is the frequency of your top offs (which need to be more frequent like i said above).

If you're dead set on not having to top off every day or so, then at the least get an ATO (auto top off unit), and have that top off the system for you
 
Yes, I agree with sir dudeguy. You NEEEEEED to be topping off much more than every 4 days. Without sealing the system off, and inventing very, VERY creative ways of introducing fresh oxygen. In a 40 with a 20 gallon sump(just a guess on size)will have about 3/4 gallon a day(also dependant on ambient humidity), and that will drastically change your salinity every day. With 60 total gallons, you could probably top-off once a day, but 2x a day would be better.

I top off with 32 oz. of water, 2x a day in my 20 gallon tank.
 
There are lots of ways to limit evaporation. Covers on the tank is one. You do need openings for gas exchange and depending on lights and temperature of your house this could cause overheating, but it is an enormous help.

reducing air flow over the top of the water will also help. For example if you have a fan on your lights make sure the air is not blowing on water also this increases evaporation.

Humidity of the surrounding air plays a role. Keeping the air around the tank humid limits evaporation.

Having a top on the tank is probably by far the biggest factor though. One it reduces airflow across the water, keeps the air above the tank humid, and some of the water that does evaporate will usually end up back on the tank (you can see it return to liquid form on the top of the lid and it drips back in).

Your sump and how much turbulence in that process plays a role as well. Clearly you dont want to create a system where your water gets no gas exchange and there is no turbulence, etc. You can find a middle ground though to drastically limit evaporation while still not hurting your tank.
 
Topping off too seldom will create wild salinity swings which will irritate or even kill livestock. Topping off at least twice a day will keep the salt levels nearly constant. I top off twice a day, morning and evening. Don't take offense at this, but if pouring a little water in your sump once or twice a day is too much bother, you may be in the wrong hobby.
 
Interesting that the evaporation cools the system. I moved my heater into the skimmer holding tank (outlet) to increased real estate inside my 55g. And a friend of mine had the same skimmer and that's what he did with his..

However, I'm having around 3 degree temperature swings. During the day (when I limit the heat in the room since no human sare home) the temp will drop down to 74. At night When we're home it jumps to between 77 and 78. So, could I keep the heat in the tank warmer and more constant if I had a glass cover over the tank at least?

I'm afraid that when I add fish that temp swing may be too much... In the summer, I expect the room will hit 80 at times. Though I do have central air and can control the room temp a little better than the electric baseboard heating temp.. The thermostat on the heater (brand new heater) is set to 80. It's a 250 watt marineland Pro stealth Shatterproof.
 
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Invest $50 in an Auto Top Off...it will become your favorite piece of equipment on the system. Just think of the possibilities...not having to drag buckets of water and top off the sump every single day. They should sell ATO's with new tanks...
 
I agree with the others. Get an ATO, or top it off yourself more frequently. Also, 74 is too low IMO. Bump up the heater and get it closer to 80.
 
I don't think it's been said...not sure if it needs to be...but just in case... Your daily top off needs to be plain RO/DI water, not saltwater.
 
I don't think it's been said...not sure if it needs to be...but just in case... Your daily top off needs to be plain RO/DI water, not saltwater.

Not trying to hijack, just want to say thank you to cozmo. I am getting ready (researching at this time) to switch from FW to SW and this is great to know.
 
Invest $50 in an Auto Top Off...it will become your favorite piece of equipment on the system. Just think of the possibilities...not having to drag buckets of water and top off the sump every single day. They should sell ATO's with new tanks...

+100000000000


Seriously. I cannot imagine not having an ATO, and I can't believe I ran my tanks for so many years with out one.
 
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