Help me keep an Open mind about Closed Loops

[AbraxasFrog]

A closed loop system is an ideal setup for me. I will be doing my own drilling, so the possibilities are many for the setup. However, I am still uncertain as to where the fine line between "just-enough" and "overkill" may be.

Consider, if you will, a 70G tank. Ideally, I would like a system that could carry a wide range of flow rates (5x-20x Tank volume). This of course depends on the return pump and/or wavemaker, but i am leaving those decisions aside for the moment. My primary concern:

1)Is it wise to drill more than a couple bulkheads for the closed loop? For example, one intake to the pump and 3 for the return.

2) How much direction is needed? In a perfect world, the flow rate would be the same whether you had 1 or 30 closed loops, as it is dependent on your return pump. More holes would mean directing the flow differently through the tank. This is preferable to a laminar flow - but how much multi-directional flow do you need?

While I know a lot depends on personal preference and what you might be keeping in-tank, I would love to hear suggestions on a) how many loops you are running, and b) the placement of said loops (at the top, at the bottom, on the side).

Sometimes, I just get this image in my head that several flow returns at high rates would be great for the anemones and such, but would send a little clownfish spinning into an uncontrollable vortex of doom. :(

[frank2926]

well if you think about it this way. If you went with 20x turnover in a 70 thats 1400gph. If you divide that by your 3 return lines thats only 466gph per return exit.
As for the feed for the loop, mine is about 1/3 of the way down.
high enough I can reach it to clean the screen and low enough that when I do a water change it is not exposed. As for the return portion, You can just drill one bulkhead in the middle of the tank and run the plumbing inside the tank with tees to any where in the tank you would like. The plumbing would be hid by the rock and will be covered with Coraline usually before even the rock is.
I put 2 bulkheads in for my loop return and teed both of them off. I use a 3600gph divided by 4 returns comes out to 900gph a return . For a 70 I would 2 return lines and tee one or both for 4 return line exits. I would only see a need for 3 bulkheads for a tank with 2 overflows to go around.

[AbraxasFrog]

<a href=showthread.php?s=&postid=13317403#post13317403 target=_blank>Originally posted</a> by frank2926
You can just drill one bulkhead in the middle of the tank and run the plumbing inside the tank with tees to any where in the tank you would like. The plumbing would be hid by the rock and will be covered with Coraline usually before even the rock is.

See, this is exactly what I love to hear! I got so caught up thinking about drilling that this simple solution didn't even bother to occur to me. You have just given me a great, fresh take - and plenty to think about!

Anyone else have innovative (at least to me!) ways that they plumbed their closed loop?

[AbraxasFrog]

I just thought of another question as well - the external plumbing could be made with rigid PVC pipe or flexible tubing. Is rigid piping undesirable because of noise/vibration?

[frank2926]

Rigid pipe is fine. To eliminate any noise from vibration just use a few inches of flex pipe or tubing at the end of the run