40G breeder LPS tank is about 1 gallon per day.
75G softie, zoa/paly tank is a little less than a gallon per day.
120G SPS higher flow tank is just over 1 gallon per day.
I have about 80G total water volume and go through about 1/2 to 3/4 G/day in the summer and about 1 1/4 G/day in the winter when the furnace is running and the ambient humidity really drops.
A bit under average I guess then with 1.25 --> 1.5 gallons daily on a 125g system (175g overall) LED's have certainly reduced my evaporation levels from previous lighting types.
Thanks for your replies guys. I was trying to get a rough idea of what was normal. I filled up the ATO container and was near empty this morning. Roughly 2-3 gallons was used. Salinity has been consistent and wasn't off when I checked.
Dwayne...thanks for asking this question. I've always thought the 2.5-3.0 gallons per day on my 120g was a lot, but according to Randy above, it's rather normal. A/C is always on where I live. Bottom line is I need a larger reservoir!
75g display + 30g frag + 25g operating volume sump and lose 32 ounces a day... BUT everything -- including much of the sump -- is covered. If, for example, i remove one of the covers from my frag tank (there are two pieces), my water loss increases to 64 ounces (1/2 gallon). I bet i'd easily be up to 2g per day if I remove all the covers.