Closed Loop Design Advice

[Osric]

I am just about to pull the trigger on approving my new 220 gallon tank, and after much vacillating back and forth am still not 100% decided on CL or no CL.

The current design looks like this:

The two large holes on the rear of the tank are the CL intakes, and the 6 smaller holes are the CL returns.

I am considering running two Vectra pumps, for maximum controllability/flexibility to use the CL for both straight up flow and turbulent flow.

Really keen to get criticisms or alternatives to this plan; not dead set on CL, could easily go with Vortech propeller pumps on the rear glass under the overflow instead.

Let the debate begin!

 

[Osric]

Crickets?

 

[Johnseye]

Just replied to your PM. I almost went the CL route but backed off. Every hole you drill is another failure point. You can get the same amount of flow by using properly placed powerheads. Question is, do you like plumbing/lockline or powerheads for aesthetics? If you don't like the look of powerheads is it worth the risk of a leak? I am sure a lot of people with CL will tell you they have no problems, or the problems they have are minimal, but there are some who will tell you of disasters.

 

[Four drachma]

I just set up a 400 gallon tank, and I have a CL. I like the idea of water being drawn through the live rock and reducing more dead water space. I used good quality bulkheads and so far no issues at all. I agree that there's always the potential for a leak around any plumbing connection, but I really like that I'm not having to pull circulation pumps out and cleaning them all the time. I also wanted an exterior pump in another adjacent room to reduce noise and heat transfer to the DT.

If you do choose to use a CL system, all I can say is really think about how your rock scraping is going to be laid out so you can hide all the plumbing without having rocks so close to the glass that your cleaning magnet doesn't get inhibited.

Good luck!

 

[kewadiak]

One bad thing about having holes drilled in the bottom of your tank is if your bulk head leaks it really sucks like what happened to me today i was redoing my closed loop and while tightening the valve i moved the bulk head and luckily i got it fixed but just another failure point if i went back in time I'm not sure i would do a closed loop. The gyre pushes a ton of water and doesn't look bad at the top of a tank check out my thread 270 rimless you can see my closed loop set up.

 

[chimmike]

can't hurt to use silicone on the tightening nut on the bulkhead for a closed loop so the above doesn't happen during maintenance.

 

[kewadiak]

Closed Loop Design Advice

can't hurt to use silicone on the tightening nut on the bulkhead for a closed loop so the above doesn't happen during maintenance.

You mean on the valve unions? I did end up doing that yesterday good tip! I just ended up going a little to much even tho they just need to be snug I was rushing....as you can see in my picture there is no easy way to tightened this schedule 80 bulk heads b/c I have 3/4 plywood down a had to use a flat head and a hammer to prevent 270 gallons of water on the floor!

 

[chimmike]

I mean on the nut that secures the bulkhead, the plastic nut. IF you use a dab of silicone between it and the glass, that could help lock the bulkhead in place to prevent minor jarring from moving it.

 

[Johnseye]

I mean on the nut that secures the bulkhead, the plastic nut. IF you use a dab of silicone between it and the glass, that could help lock the bulkhead in place to prevent minor jarring from moving it.

If you mean use silicone between the bulkhead and glass don't do it. The seal will slide allowing a leak.

 

[Mrramsey]

Something I considered after I built my tank was to make a hybrid closed loop for better flow. I don't like the idea of more holes in the tank either. My idea was to go over the top with a return plumbed all the way down to the bottom of the tank. Then distribute through pvc that would be covered by rock and sand thus keeping it all internal to the system. There are some caveats to doing it like this though such as independent flow control. The idea would require a much larger pump.

 

[Four drachma]

Osric, are you still looking for closed loop suggestions?

 

[Osric]

Whoops sorry for not closing the loop on this one. After much agonizing, I decided against getting the tank drilled for CL and am planning to use 3 MP40s for flow instead.

I couldn't find enough support for CL as the best way these days, though I'd really wanted to do it.