Water evaporation

Just a quick question.
My tank is hoodless with a lighting fixture over it.
Does the water evaporate the same ammount with a hood/canopy
vs open top?
Thanks guys
Just curious cause every 2 days i have to add a gallon of water to my 29g long (hoodless)

 

it will most likely evaporate less with hood but it is better to let air flow and have good gas exchange.

 

I have a canopy over open water with t-5 and fans I loose 2 gallons a day!!!

 

I add about a gallon a day to mine as well.....maybe a little less. Sounds about right. If you keep a glass top over it, it will not evaporate as fast, but then you suffer the consequences of inhibited gas exchange. A canopy doesn't make much difference unless it lessens air flow over the water surface (from an open window or such). In that case, evaporation would lessen.

 

I run an airpump in my aquarium, always have in everyone i have owned. If i covered the top and continued to run the airstone wouldnt i get good gas exchange?