700g overflow?

[hawk70]

is 700gph overflow enough overflow for a 75g tank?

 

[squidd]

Depends on a couple of things...
1.How much will your return pump be puting in the tank?
(You want your over flow closely balanced to your return gph, but slightly favoring the overflow...more overflow than return or you will overflow your tank.)
2.Will you be depending on OF/Return for TOTAL Turnover or supplementing with powerheads?
(You want 10x to 12x per hr. turnover,some say as high as 15x. A 75gal would need 750 to 900+ gph Total turnover, so you would need a PH or two in addition to the 700gph overflow and pump, or "about" a 1000 gph. OF/Return and a spreader/spraybar if you dont want any PHs in the tank.)

 

[stumpdog]

You may want to consider getting an 1400 gallon overflow. I know you may think it is a little much, but it gives you some flex room. If you plan on upgrading you already have a bigger overflow. Plus 1400 gallon wouldn't even be a 20 time turnover in a 75 gallon tank. Just something to think about. HTH.
Jeremy

 

[nm reef]

If you were interested in maintaining a fish only system then your choice may be enough. But most reefkeepers prefer way more turn over and 700 GPH on a 75 wiould be considered minimal.
Just for the sake of comparison I run a pair of 700 GPH overflows with a MagDrive 1200 return pump and 6 MaxiJet 900 powerheads on a 55 gal reef.

nmreef@cox.net