Yeah that sounds about right, I go thru probably 2.5 gallons in my 17 gallon in 3 days. As long as it's operating correctly, as in, your float or switch isn't stuck or malfunctioning and your supply hose from the ATO reservoir isn't siphoning water back out and water isn't leaking out of your tank, lol, it sounds like everything is going smooth. Evaporation is also very important bc it helps with gas exchange.
One problem this made me find was the water did start back siphoning once the reservoir level got low enough. Good call. ATO is still running frequently but from some research it is apparently normal.

