connecting 2 overflows

[ha-y-n]

I have a drilled tank and i wanted to know if i can use both of the holes for drains to the sump by connecting them together somewhere along the plumbing. If so how would i do this? Thanks

 

[nm reef]

Sure...they can both be drains. My 100 is set up like that. I have a single cornor overflow with two holes...one for a drain the other is designed for a return....instead I use them both for drains to my sump and used pvc lines for returns.

 

[dogstar]

You can run both drains seperately to the sump OR like your asking, Bring them both together to a T or Y fitting that is the size of both drains together. If one drain is a 1 inch and the other is a 3/4 inch then the fitting should be a 1 1/2 or 2 inch and use reducers to fit the pipes to the fitting. From the T or Y run the same size pipe that the fitting is to the sump.

 

[pontius]

ok then, if you are using say an All-Glass tank with an overflow rated at 600gph and use both holes for draining, what your approximate gph be then? I assume you'd have to then use a stronger sump pump right?

 

[murph]

Two one inch drains will handle 1200 GPH. I am assume PVC here, so if you only want one drain where the water enters your sump you will have to tee the the two on inch drains together but where the water leaves the tee going toward your sump you will have to use and adapter out to two inch PVC to the sump. I hope that made sense.
You may also be able to find a one inch to two inch T which would be the ideal situation. While you are at it I would put a threaded coupling in the two inch PVC as close to the tank as possible to make things easier to clean or, God forbid, the tank has to be moved.

 

[ha-y-n]

thanks for the help guys. My tank is a 72 gal, and the two drainlines is a 1" and a 3/4" from the corner overflow. So that would make it about 900gph(?) i think. Would it be a better idea to run the 3/4" straight to my small refuge side of the sump, and the 1" straight to the skimmer side of the sump? Or would that reduce my flow? I wanted as much flow as possible coming from the overflow so i was thinking of connecting the two drainlines together first, and then adding a tee with one line going to the refuge with a GV and the other line going to the skimmer. My sump is a 29 gal. Any help would be appreciated.

 

[fraggle_a]

What you need to worry about is the return pump.
If the return pump is moving more water than can fit through the pipe then your going to dry the sump.
Remeber, in an overflow the amount of water that exits the tank is conditional on the GPH of the pump putting the water back into the tank. You can run both holes, but it may not make things more efficient.
Id choose to run both, and possibly increase the sump, or pump GPH.
(but dont put a big pump on a small sump or your going to have problems)

 

[ha-y-n]

i dont think i can get a bigger sump because of the limited space in the stand. Im thinking of running a ASM G2 -10" x 11" footprint.... and a pump -didnt buy it yet but planning on an Mag 9.5 (800 at 4') or 12 (1100 at 4') and their footprints are about 5.5 x 3.5 and 6.5 x 4.5 ......along with a small fuge. Does this sound right? What do you mean by having too big a pump in a small sump?