How do closed loop systems work?

[BowieReefer84]

Please explain how a closed loop system works assuming I know nothing about them. Everything I am able to find assumes you have some knowledge on the subject, which I do not. Do you hook it into your overflow? Is it separate from the sump? How many pumps? I know nothing . . . .I plan on doing some SPS, and I hear this whole closed loop thing is nice.

Thanks in advance.

 

If anyone has pictures, diagrams, or links to build threads that would be great.

Edited June 18, 2010 by BowieReefer84

[Coral Hind]

A closed loop basically pulls water from the tank and returns it directly to the tank. It is used for circulation and not for filtration. There are many ways to setup a closed loop. Some use bulkheads through the glass or you can go over the top. Here is a nice image of two closed loops.

 

 

Here is a simple over the side closed loop.

http://www.melevsreef.com/closedloop.html

 

I would recommend getting out to view member's tanks and see how they have their closed loops. Some of the LFS also have closed loops on the in store tanks so ask them the next time you stop in if they can explain the setup.

[BowieReefer84]

Thank you for that detailed drawing. Makes sense.

[zygote2k]

I had a closed loop on my old 120. I thought it was an extra thing to worry about because of the extra pump intakes that might slurp up a fish or a wandering anemone. Remember those kids that drowned at the bottom of the swimming pool because they got sucked down to the bottom at the circulation drain? The same thing can happen in your fish tank with a closed loop.

A closed loop might be good on an enormous tank where it would be cost prohibitive to use powerheads, but since you're going to use a small tank, why not stick with 2) mp10's or 2) mp40's? If you plan the rockscape wisely, you'll get the proper flow that's needed just fine.

[BowieReefer84]

Rob,

 

Although I never knew any kids who drowned by being sucked down to the bottom of a pool, I do agree with you on the rest of your statement. I am not going to go any larger than a 90 gallon on my next setup. I was under the impression closed loop had something to do with filtration. Now that I realize it just circulates the water I will likely do power heads. If I use those column rocks I posted previously in another thread I do not see there being any issues with flow. Thank you for your comments. I hear that pet place sends out coupons every so often to be used during the week. One of my good friends is a teacher and does nothing in the summer. If I get one, maybe he will make a weekday trip up there (only about 1.1/2 hours from him). Those MP series pumps cost soo much.

[Glenn]

I actually do remember an article about a kid who went to the bottom of a community pool to sit on the drain, and then drowned when he couldn't escape the suction.

 

Coral - nice drawing of simple closed loop ... do you have anything showing how the more complex one would work? Specifically, what about the "Oceans Motions" (OM4 ??) think makes it different.

[Coral Hind]

Here is one Glenn.

 

[DaveS]

Here are some pics of a system with 2 OM4s: http://www.wamas.org/forums/topic/30935-daves-210-redux/page__st__25__p__297502entry297502

[BowieReefer84]

Here are some pics of a system with 2 OM4s: http://www.wamas.org...02entry297502

Wow. Don't think I will ever be on that level. Not that I wouldn't like to, but that must have costs lots of thousands. Plus to fill something like that with livestock . . .

Very nicely done.

[Jon Lazar]

Here is one Glenn.

 

 

This may not be your picture, but what's the purpose of the white vertical pipe that rises up through the overflow box? At first I thought it might be to prime the pump. But the pump is below the two inlets inside the tank, so I think the pump will be self primed.

[Coral Hind]

Removing the screw cap allows the air to leave the system. Since the returns are below the water line the air can be trapped and not allow the pump to prime fully.

 

 

[Glenn]

That answers my question -- the OM4 only handles the output. There is one or more separate lines that feed the pump. Thanks

[davelin315]

It's purely for circulation purposes. I hate having any powerheads in my tank so I have 2 closed loops. There are cons to them, but I think the pros far outweigh them. For instance, maintenance can be easier by simply closing off some valves and then having the pump right there. With any powerhead in a tank, you always take the chance of a fish getting sucked into them or electricity leaking into the tank, whereas with a closed loop, you don't have that. There's also little to no heat transfer due to the pumps being out of the tank and you are also getting more bang for your buck - the feed can increase current in areas of your tank as well as the return. For many years I had powerheads buried all over my tank but when I got sick of seeing them in the tank and went with closed loops I increased my flow in my tank a ton and also didn't sacrifice any room in the tank for the placement of a powerhead. I have not used any of the Ecotech vortechs or the Tunzes or similar "powerheads" but don't feel I need to, either. If you take a look at my tank you'll see my system has 2 barracudas that power my 2 closed loops. I have one powerhead in my system which runs a calcium reactor and 3 pumps for my protein skimmer which are all run as external pumps, so I have nothing electrical in my water at all (the calcium reactor is not hooked up right now). Check out my build thread and the before pictures of the tank show my closed loops. They are not for all, but I think any system that uses one can be very successful (I set up a 1 gallon jar that I drilled 2 holes in the bottom of and used a canister filter filled with rubble in it for a closed loop and it's been running at the neighbor's house that bought it at a cancer auction for over a year with a damsel in it) if tailored to your needs.

[rioreef]

Not to start a discussion on UV filter, but if the flow is sized to match the capacity of a UV filter, one could be added in-line on a closed loop.

[DaveS]

Not to start a discussion on UV filter, but if the flow is sized to match the capacity of a UV filter, one could be added in-line on a closed loop.

 

Or chiller! and if the flow out of the pump is too high, you could plumb the UV/chiller/whatever after any splitter to just one of the returns. One thing to keep in mind is to make sure the intake/drain isn't in an area that will suck in debris. That's not good for the pump or anything else.