Is this normal?

[hank]

I have a setup I got used, and this is all new to me. The tank is a 72g bowfront,sump 17g?, return pump Rio 32H (1500gph @4fhp). I filled tank on Tues. then on Wed. pump was sucking air- so I added 1g water. Now again today Fri. it was sucking air again, so I added another 1g water???
Is the return pump too strong or is this normal?
Hank in SoCal

[Irvine]

It depends on what you have for an overflow, is it the hang on back overflow or is it a drilled bulkhead? If it's an hang on overflow then the flow rate (GPH) may be considerably less than your 1500GPH return flow. you need to balance the flow. either get an overflow that can handle a higher flowrate, or get another return pump with less flowrate. hope this helps.

Also, you may want to get a larger sump to give you more water volume to work with.

[hank]

It's a drilled tank, the ID of the hose going to sump is 1 1/4" and the sump is 17g. When running the sump is about 1/3 full. Thanks, hank in SoCal

[Frogfish]

your water is evaporating! You have to replace it with straight water (not saltwater)

This is common and about 1 gallon every couple days in your case is about right depending on the humidity in the house.

[mad_dog01]

I lose between 2-3 gals a day from evaporation. depends on your lighting also if it is causing your tank to heat up. But you have to add water daily by the sounds of it. I have 1 gal milk jugs set up daily mixed with Kalk mix to fill my sump up from the evaporation. If you don't want to do it manually you can always get a RO unit with an auto topoff and you really will not have to mess with added water just changing filters in the RO unit.

[hank]

Thanks, another day another mystery.
Hank in SOCAL

[luke33]

FWIW, you may want to pick up a larger sump for that much circulation. That way you won't have to worry about your pump burning out because of running dry. Just my .02$ Rubbermaids work well and are cheap!