Got my 320 gallon today, powerhead/sump Qs

[rallysman]

If you're going to use the returns on the back of the tank (I would--those flexible extensions aren't cheap) then plug the return holes for the overflow.

1 overflow on each side, and use the returns on the back. Without seeing the highest return I would say use a check valve (any hardware store will have it) for the return line.

 

[easydoesit]

okay. the highest return is about 4-6 inches lower than the overflow line.
what do you mean by plug the return holes for the overflow?
sorry for my newbness.

 

[rallysman]

each overflow box should have 2 holes in the bottom. If not, don't worry about it. If so, don't use them if you're using the returns on the back. I think the easiest way to prevent backflow through the returns (during a power failure) is to use a check valve on the line that supplies the returns.

 

[easydoesit]

true. alright, sounds good... thank you for the help