Calculator
How fast does my tank evaporate?
Calculate daily evaporation in gallons + suggested auto top-off (ATO) reservoir size. Surface area + temperature + ambient humidity drive evaporation rate.
Inputs
Enter values + click Calculate.
How it works
Step 1Open-top reef: 0.5-1.5% of volume per day
Step 2Lidded freshwater: 0.1-0.3% per day
Step 3Sump-equipped systems evaporate faster (more agitation)