plumbing questions for a 240

[Diatom2]

ok so I bought a new 240gal 72x24x30 and I'm going to have it drilled. My plan is to use a mag 24 for a return from the sump and to have a closed loop as well as 2 streams for interior circulation.

Now the questions:
1) which would be better one center overflow or two corners?
2) how many drain holes and what size? I assume one return will work.
3)where would you place your inlet and outlet holes for the closed loop?

Any other ideas would be much appreciated.

TIA,
Brent

[rji1966]

i have the same size tank. I have two-two inch overflows with screens. The water is about an inch high on the screens. If I had to redo I would like to puthave as much linear overflow as possible, like the entire length of the tank. On page 42 in The Book of Coral Propagations, by Calfo there is diagram of what I would do next time. Any way I always drill for two inch bulkheads on all overflows, you could always reduce the bulkhead, but you can't make it larger. I always drill for 1 inch returns, again could always reduce to 1/2 or 3/4 inch if you had to but can't make it larger. Oh well just something to consider. Bob.

[AuroraDave]

Here are some flow estimates based on the size of the overflow teeth from Tenecor:
1-1/2" teeth, get 100 gph per inch with 1" drain (12" long is 1200/gph)
1-1/4" teeth, get 83 gph per inch (12" long is 1000/gph)
Eliminating the teeth and using a screen or egg-crate will increase the through-put by 1.5 to 2 times.

It's hard to answer #2 & #3 without knowing what corals you are planning & therefore how much water circulation you will need. Depending on the pump size one or two returns will be plenty from the sump. I use 1 with a sea swirl & a 1140 gph pump.

My closed loop has a 2" drain and six 1" returns powered by 4000 gph pump. The returns are plumbed w/2" PVC all the way to the bulkhead where I reduce to 1" at the last minute. I split two of those six returns a second time inside the tank with Loc-Line, so I have a total of (8) returns with 3/4" loc-line off the CL pump.

Drill the closed loop drain in a location with easy access so you can clean the strainer.

[Toutouche]

I agree with Rji1966 about the full length overflow. It is the "best" way to skim the surface. Ufortunately, not eberyone has a setup that this can be done on ( myself included as my tank is a see through). One good idea about the closed loops I saw in the historicaly long thread about Weatherson's setup is to have the intake of a closed loop at the opposite end of the tank as the return. This way you know the tank water is really getting mixed. If you can't go with the full length overflow, then 2 overflows ( one at each end) is always a good thing to keep the surface clean of buildup. However, most people think that you need all this circulation actually going through your sumps and is why they put multiple overfloes but it isn't so. The important thing is "intank" circulation and water movement. Keep in mind that if you use more than one overflow, it is adamant that they are exactly equal heights or you'll get some draining fluctuation between the two which can cause hassles at times or noise.

[Diatom2]

Thanks for all the advice guys. I'll look into setting up a full lengh overflow along the back of the tank.

I'm wondering about the need for a closed loop with the two streams. I guess drilling for them and not needing them would be better then the alternative, and at $15 a whole it's not much of an expense.