My tank has a full hood but it still loses about 1/2 in to an inch of water during the week (depending on how dry the weather is). I also have large cut outs on the back for the filter and heater which may also cause issues.
I'm mainly asking because the tank I'm putting together now doesn't have a hood. I'll be making a makeshift top out of mesh and sharing the light with my other 10 gallon until I can afford a light for it. I think without a proper hood I'll have a lot more evap.. Its not going to matter much at first because I need to get a filter of some sort before cycling it. I bought a used filter of UB and she didn't send it with the intake
. And she hasn't PM'd me back about it either. I can't use the darn filter without an intake :(