Evaporation

75g with 20g s/f - 5 to 6 gal per week.

 

so in my 90 g im replacing 15% of my water every week ontop of my 15 - 20 % water change is this normal?

 

Don't worry about it. Whatever it turns out to be is what it is. It is totally normal for your topoff volume to vary regionally and seasonally. It also depends on your tank set up. For example, I have a 20g tank with a 10g sump and neither tank has a lid. Because the system is very open and I live in California, I may sometimes have to replenish an entire gallon everyday. Fortunately I live near the ocean and on other days it is cooler or more humid so the evap is less dramatic. I need to invest in an auto-topoff system to save myself labor. Have you considered doing the same?

 

Right now in the winter I am going through about 15 gallons a week for two 75gals

 

I think open tanks is what Is doing it. I have replaced 1 gallon in a week with my 75ish gallon tank no sump with glass cover on top all but about 1.5 inches.

The sump adds alot of open tank as well I take care of a 85 with 40 gallon sump and it takes about 6 gallons a week in a Dr.'s office that stays at about 70 F

 

It doesn't sound to me like most go through 15-20 gallons per week... I wouldn't agree with that statement.

 

There is no doubt that the open tanks exacerbate the evaporation problem. Nonetheless, the ambient environment is still going to factor in.

 

That sounds about right I think. It also depends on how dry it is where you are and where the tank is etc... here in the winter it's terribly dry, I don't know how California is.

 

California has wet winters in general, although we have been in a drought recently.

Someday I will have an autotopoff. Doing it by hand everyday gets old.

 

75 tank w/ 29 fuge and about 1 gal a day