fishlvr13

The water level in my fish tank has gone down a couple centimeters or so over the last couple days. I think it is just evaporation because I checked for any leaks and i didnt find any. Its not a big deal, but it makes my tank not look as nice because the water level is visible. Is it ok if I add in a little bit of tap water to help raise the water level - or should I wait until i do a water change?

Thanks for your help!!

Kuli_Loach

I don't think it would hurt. Do you have an aireator on yours? I have one on mine and it causes a lot of evaporation but I change my water a lot right now due to a disease.

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Too Many tanks!!!

ZeroSystem

Glass tops can help with evaporation problems, they're much better at preventing evaporation then plastic hoods. In the summer I usually keep a 2 liter bottle (thats been rinsed out very very well, of course) filled with dechlorinated water next to the tank so I can top off any evaporation that may happen before I do the weekly water changes. I believe even small amounts of chlorine can be stressful on fish and devastating to beneficial bacteria.

Tommy Gun

Water evaporation is completely normal and is something to be expected. Even with tops, water will evaporate. The last thing you want to do is create an air-tight seal on top of your tank in an attempt to slow or stop evaporation since this could result in low O2 levels in the water, which you fish will need. You can 'top-off' your tank as needed with dechlorinated water like Zero points out. I probably add about a gallon of water to my 90 gallon FW tank every two or three days and I add about 5 gallons of water to my SW tank every other day. Evaporation rates will vary depending on your geographical location and weather patterns...and I am sure that airstones may add to evaporation, but only in a very minimal amount, if they do, so I wouldn't turn them off or refrain from using them simply for evaporation reasons.