Is this enough overflow?

[kidafius]

For a 120 Gal tank, is 1 overflow, (about 7"x7") enough or should I install another? Its a 2-sided corner overflow.

How large is the drain hole and what pump where you planning to use as a return?

It will also be affected by head pressure....

Cheers
Steve

[kidafius]

the hole is about 2 inches, and I plan on at leat a 695 gph return.

[fishfreek]

If the hole is 2" diamater than you will be fine with just 700GPH flow rate.

Originally Posted by kidafius

the hole is about 2 inches, and I plan on at leat a 695 gph return.

A pump at 695 GPH would be fine for that overflow, but I hope you are also supplimenting the total tank GPH with some additional water flow from another source. With most pumps at 4' of head pressure the GPH will fall closer to 500 GPH and give you a low tank turnover.

A few well placed powerheads will easily correct that though...

Cheers
Steve