Overflow valve

[cozzar]

Greetings all.
I am near completion on our new 90 gallon tank and was tonight getting all the pipework together for the overflow into the sump. My question is:-
I have a valve to install in one of the lines and am not sure which line it goes on or what its purpose is. To regulate waterflow ok but why do I need to regulate it?
I have 2 outlets and 1 return line.
Cheers
Andy

[Misled]

Put the valve on your return. Depending on the return pump you use, you may want to cut it back to slow the water through your sump. If you put it on the "outlets" the pump will overflow the tank if you back it off.

[jtrim123]

What kind of valve is it? A ball valve(adjustable) or a check valve. Either way you will want it on your return, as your overflow will only run at the rate the water is coming into the tank.

[cozzar]

Thanks all. The valve is a ball valve.

[Misled]

The valve is a ball valve.

Good, that's what it should be.