Closed loops for planned 240 gallon tank

drblank1 · #1 11/12/2004, 01:11 PM

I have decided to order a tank that will measure 72x31x24 (LxWxH). I will have the manufacturer drill the closed loop holes. I will be using (2) Mag 36's for two seperate closed loops (a total of 7200 gal/hour). This tank will be mostly dominated by SPS corals.

I would appreciate any suggestions for the following:

1. Quanity and size of bulkheads for the intakes of each loop.
2. Quanity and size of bulkheads for the outlets of each loop.
3. Suggested placement of holes in the back panel.
4. Is 7200 gal/hour enough water movement for a 240 gallon tank?

I am new to the concept of closed loops so any help would be greatly appreciated.

Julio · #2 11/12/2004, 03:00 PM

how many intakes and returns are you planning on having?

PRC · #3 11/12/2004, 04:03 PM

Those are about the same dimensions as my tank. I've got two Iwaki 55's on closed loops. Each has it's own intake 1" bulkhead. Mine are drilled in the bottom of one end since the tank is setup as a room divider. If I were going to do it now I'd put them up on the side instead of the bottom. Less to worry about if a bulkhead leaks, and far easier to fix it. I'd go with bigger intakes, say 1.5" if I could have.
I've got ten returns in the tank. One in each corner and two in the center bottom, one front and one rear.
I would probably go with Sequence pumps now for that kind of flow. I think 7200GPH should be great with whatever your sump return is on top of it. That'll give you somewhere around 30x - 40x which is what I'm shooting for eventually. I'd also think about using eductors if you have the room.

drblank1 · #4 11/13/2004, 10:25 AM

Julio, I'm not sure what I should go with so that's why I'm asking those reefers with experience. I don't want to restrict the flow of the pumps in any way, so I'm not sure what size and number of holes make sense. Each hole will cost me $20 to drill so I would like to balance cost vs. number and size of holes.

PRC, because of my setup (in wall), I can have my holes in the sides or back panel. I do not prefer the bottom. Also, I have not decided on my return from my sump. I am considering between 1200 gph pump or 2400 gph pump. What do you think?

drblank1 · #5 11/15/2004, 12:10 PM

bump

PRC · #6 11/15/2004, 02:00 PM

The return is dependent on your overflow. The pump should be sized to return a bit more than your overflow can handle. There's a calculator on RC for overflows ( http://reefcentral.com/calc/drain.php ). I think the calculator is a little conservative because I have a 1" bulkhead in my overflow and I run my Iwaki 55 flat out which should be very close to 1000 GPH, the calculator says a 1.31" drain should be required.
For a 240 I would probably try to go with two 1.5" bulkheads (not sure how big the hole needs to be for that) and around a 1500GPH pump, probably a big Iwaki or a small Sequence. Always better to oversize things a little since you can always throttle back the overflows and the pump if you need to.
I'd put the returns from the sump in the bottom of the tank to provide better oxygenation.
I also have a couple of Seio's in the tank to provide a little more flow and as emergency backups for power outages (they'll run far longer on battery backups than the Iwaki's). You could use a Tunze or two for this purpose if you have cash to burn.

drblank1 · #7 11/16/2004, 02:17 PM

I did some research on the Tunze Stream pumps and it looks very interesting. I really liked the Tunze Turbelle Stream Kit TS24. I like having a controller to simulate wave and night conditions and the price seems right.

I think what I would like to do is have the closed loop intakes on the side panels in front of my "wall of rock" and have the outputs blast the back of the rock work so the water moves through the rockwork. And then have the Tunze Streams blow accross the front of the "wall of rock" over the corals. Would this be a reasonalbe configuration?

Now my question is: Having 7200 gal/hour closed loop flow and adding this Tunze package with 6350 gallon/hour flow, would 13,550 gallon/hours be too much flow for a 240 gallon tank(~56x)?

drblank1 · #8 11/18/2004, 10:29 PM

Can anyone answer the 2 questions I asked in the above post? Please....

PRC · #9 11/19/2004, 11:54 AM

I hope you're not planning on having any sand in this tank. At least not on the bottom of the tank, anyway...

I would probably cut back on the closed loops if I were going to invest in the big Tunzes. I'd cut it back to one pump at least, maybe even a smaller pump. Remember, though, if you're using the controller to run the Tunzes in an alternating fashion you won't get the full 6350GPH out of them. Probably more like 3500-4500GPH average.
The price seems right, eh? That's gotta be the first time anyone ever said that about Tunze...