Sea Turtle":2dun1yf5 said:Sounds ok to me. I have a 75 gallon with a 30 gallon sump and I replace about a gallon per day. maybe a little less. I use a humidifier in the livingroom that puts about a gollon of water into the air per day. I have noticed that this has significantly cut down on the evaporation from the tank. You can get a nice one at home Lowels for about $40. Plus it helps keep your house warmer and makes your house heater more efficient.