Question on closed loop circulation systems

[yabby]

Ok that sounds neat-if the 2 return pumps fail- then the Dorso's will continue to suck water down to the sump until the water levels falls below the edge of the Dorso's lip (that's also below the level of the overflow).

Then the circulation pump sucks the REMAINING water in the overflow back to the tank, which then falls back into the overlow, then it cycles about

that what your thinking?

Sounds good , but that's a load of water going into the overflow. You will have to put strainers at least on the circulation inlet, cause something will certainly get swept into the overflow , ie dumb clownfish, shrimp... Otherwise I very much like the of making both/all bulkheads in the overflow removing water and use returns for random water movement.

Good luck
Paul

[ January 16, 2002: Message edited by: yabby ]</p>

 

[mariner]

With 2 drainers in one overflow, You might have to dremel the openings in the box wider so the drainage in the tank will keep up with the dual durso's. Unless that has been accounted for when you ordered it. Yes, I would also somehow net those durso's so no life gets sucked in.

 

[M.E.Milz]

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr> Then the circulation pump sucks the REMAINING water in the overflow back to the tank, which then falls back into the overlow, then it cycles about

that what your thinking?
<hr></blockquote>

Yep. The only possible glitch is that there will not be enough water in the overflow compartment below the Durso's to compensate for the rise in the water level in the tank that always occurs when the pumps are running (ie, above the edge of the overflow partitions). But I think that I will be ok. Afterall, this is only an issue if both pumps connected to the sump fail, which is very unlikely.

Inter-American Pet Supply is building the tank for me, and I have told them that the overflow must easily handle 4000 gph. From what I have seen of their tanks, they use straight edged piece of acrylic for the overflow compartments with eggcrate strainers. The eggcrate has very little impact on the flow over the partition, so the tank water level should not rise a great deal.

And yes, I plan to use strainers on all of the drains (although these will be very difficult to reach for cleaning).

 

[M.E.Milz]

I have just place the order for a new tank (78"x32"x36"). The tank will include a center overflow (a 16"x6" compartment) with 3x 1.5" bulkheads through the bottom of the tank (inside the overflow compartment).

2 of these bulkheads will be connected to my sump. Water will be returned from the sump by 2x Iwaki WMD40RXLT pumps that will direct water through a series of returns along the back of the tank.

The remaining bulkhead will be connected directly to an Iwaki MD100RLT pump. This pump will return the water through 2x 3/4" SeaSwirls. This will act as a closed loop.

The 2x bulkheads that are connected to the sump will include stand pipes (eg, Durso), but the other bulkhead will not. This way, even if the 2 pumps connected to the sump are shut down, water in the overflow should still be able to feed the closed loop pump (and without continuing to feed water into the sump).

Are there any flaws in this set-up?

 

[Jeff Hood]

The only problem I see is you may have a micro bubble problem. If your overflow is deep enough then after the tank gets broken in you should be ok. However with three pumps feeding off of your overflow you will create a lot of turbulance and thus more microbubbles. Your only other option would be to connect your closed loop bulkhead to another bulkhead through your overflow wall directly to your tank with a strainer. The only down side to this is you would have to drill another hole. If that breaks then your sunk.
Also as large as your overflow is you should have enough water reserve to easily run the closed loop when the main pumps are off depending on how much water you allow to siphen back to the sump via your returns. Just make your stand pipes as tall as you can and use siphen breaks on your returns and you will be great. You can always cut them off some if they are too tall.
I love the dimentions of your tank. You will love the depth and height of your tank. It will look very impressive. Its still plenty long for tangs and swimmers also. Good luck and post pictures when you get it.


Jeff