Closed Loop Systems

[Ken Sellick]

I am planning a 900G SPS BSD display tank and have heard people talk about "closed loop systems" I know that i want high water flow in this tank but don't know anything about closed loops. Any help would be appreciated

[VegasMike]

Closed loops are just a loop from your tank, through a pump and back into the tank. Typically, you have a bulkhead or bulheads that feed the pump and then returns the water back to the tank via another bulkhead or maybe some Sea Swirls. Some people have them hooked up to actuated ball valves which helps to vary flow. They are also quite useful in providing flow behind the rockwork. My plans are to use one Closed loop initially to provide flow mostly behind the rock work and two Tunze 6100's with a multicontroller to provide flow in the open areas. The tank is being built to allow for another closed loop and two more Tunze 6100's if I want them.

My closed loop in my current 150 gallon tank was an after thought and I just ran a couple of U-tubes over the back and down to an AM3000. The AM3000 returns water to the tank via two Sea Swirls.

[willis]

On my 300 I am gonna have 2 closed loops. One fed by a little giant 4 mdqx(?), that will feed 3 3/4" line behind the rockwork. The other one will be fed by a AM3K that will go to 4 3/4" sea swirls. I hope this will be enuf random flow!:smokin:
The tank isn't up and running yet, but it is in it's final resting spot. I'll post up some pics tomorrow if you want.

[Ken Sellick]

I have been planning 10 X/hr tank volume thru several diffusers along w/ a seperate surge system and high volume silent overflow. I have not yet finished the overflow design.
I thought i would plumb the tank with two large centeral diffusers and surround them with live rock. The tank is visable on 3 sides.

[dgasmd]

For a 900 gal tank with SPS, I would plan on 3 or maybe even 4 of the sequence 5800 pumps plus the returns from your sump/refugium, which I would use a iwaki 100 with eductors to maximize flow. I am not a big fan of the tunze streams for a number or reasons, but they are all very personal reasons.

Alberto

[Ken Sellick]

Thanks for the imput. Here is my latest concept.

[Ken Sellick]

Here is a close-up

[dgasmd]

Ken:

Very well thought out plan. However, I will highly discourage you from drilling the tank on the bottom for intakes and outflow. If those bulkheads ever leak, have you ever heard of Murphy's law?, you will have a huge problem in hand to fix it with a full tank on top of them. However, I know of a few people that have done this in the past and have not had any problems to date.

[Ken Sellick]

Originally i was running return piping from the pump over the sides and thru the DSB that is really just a plumbing concealer. I thought it would simplify the plumbing to use bulkheads.
I don't have much experience with bulkheads so this issue was a concern of mine.

[Ken Sellick]

Here are my latest design changes

[diverdon]

I have a 550g tank and i drilled 7 2inch sched 80 bulkheads and gate valves with risers into the tank and couplers, all sched 80. I also have a standpipe to connect to the bulkheads so If I need to service the valves underneath I install the riser pipe and remove the valve to work on it. This way my permanent riser is above the sand level, I have gate valves (big ones) to shut off each bulkhead and it's worked well for a year or more. I have overflow and sump return and one recirculation system in service. I've liked the bulkhead design. Two are in the overflow (4ft across the tank) and the rest are in the tank, mostly near the overflow. Now I'm adding tunze streams. I started one today and the turbulence in the tank is very nice. My dual 6100's and timer are on order now. I don't have any siphons or other piping to worry about. The other odd idea was to have a sump which is 5ft tall and raised so that the drain down will not overflow the sump. Now I don't have any check valves. On power down the tank drains to the sump raising the sump 2.5 feet and dropping the tank about 3inches. It's been reliable to date. Using the sched 80 piping for all of this makes everything much more rugged.