Fast water evaporation.

[dragonzim]

I top off a gallon a day in my open top 75.

 

[who dey]

Originally Posted by skipperdz
my 12g never needs top off...i do water changes but i may lose a gallon maybe once a month if i didnt do water changes and actually noticeda change
because you live in naples and it's warm. I was just down there last week

 

[catawaba]

Also depends on how much humidity you have in your home/area.
We barely crack double digit percentages here.

 

[craig7220]

Originally Posted by Catawaba
Also depends on how much humidity you have in your home/area.
We barely crack double digit percentages here.
Ain't that the truth..... I lose at least 2 gal a day in my 125 open top..... and thats when our humidity is high here at 25%. I usually add 1 gal in the morn and 1 to 1.5 gal in the evening....