Closed Loop - One pump (75 plumbing)

DRC Archive General Saltwater Discussion
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So I’ve been struggling with the closed loop idea, but I think I’ve got it. Basically a closed loop is just a system to circulate water like a PH, but with an external pump.

Here is my go at a “closed loop” setup with a single pump and a sump. Let me know if I’m way off base here.

Flow comes out of tank and Ts back into pump and into sump.
Flow comes into tank from pump into each end of tank.
Flow comes out of sump and Ts into pump inlet.
Gate valves on sump inlet and outlet.
Ball valves prior to pump inlet/outlet for pump maintenance.

I’m not sure exactly how Al had it setup.

I’ve attached a picture of “plan” described above.

CL_wSump.JPG
CL_wSump.JPG975×797 27.6 KB

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Almost. The water actually never gets exposed to air. You couldn’t regulate the water flow if it was in a sump. You have to have an external pump which receives water from the tank constantly with no restrictions (like an overflow) and the pump just simply pumps the water back into the tank. Make sense? Hope this helped some? I am about to run a CL on my new FO tank, but haven’t decided how to run everything or what pumps to use.

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Not quite.

First, the system isnt closed. Second, in your diagram your returns could siphon your DT if your pump lost power. Lastly, you shouldnt use gateway valves.

Its actually MUCH more simple than you think. I dont have time to draw a pretty picture, but i will try my best to explain it clearly. I will use your example with one CL drain and two CL returns. Your drain will be plumbed directly into the intake of your external pump. You will need a T with a short vertical riser at the intake. The riser should be plugged and you can thread a simple jon guest style ballvalve fitting into the plug. Your returns will will T into one pipe that you plumb directly to the output of the pump. Voila. Closed loop. No siphons, no worries. The T with riser is for pumps that dont self-prime(almost all pumps). Open the jon guest ball valve to bleed the air from the system and prime the pump. When water begins to come out you close the fitting and start the pump. You dont want to install any gateway valves. Go to lowes and buy tru union ball valves or you can get away with one ball valve and one union. I would put tru union ballvalve behind each return and the drain. You only need to put a union on the input and output of the pump. This will allow you to maintainence all of the plumbing and the pump without spilling a drop of water.

:TWOCENTS
CL’s are pretty much worthless unless your willing to invest into some sort of direction switcher like an oceans motions squirt, 4 way, or something similar. They are also pretty much worthless if you dont invest in locline for the returns. I dont think having only two returns is ideal for a CL, but if this is what your doing you can probably use a SCWD. I just think unless you have a very large tank with at least 4, 8 would be better, returns and some sort of direction switcher on the loop your better off using a couple of ultra efficient powerheads.

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Well put LD, I forgot to mention the unions and valves! Whoops! Just trying to get the basic concept down. I don’t think they are worthless though, without some sort of wave maker/directer. Linelock and having them aimed correctly is a must! I plan on running two CL on my 210 with 2 drains per each and 3 outputs for each pump, which will probably have 2 outputs on each. Now if I could just figure out what pump to go with!

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In a FOWLR you can get away with not using a current switcher. In a reef its kind of pointless. If he has only two returns and he doesnt have the ability to alternate them what good is it? It will be the equivalent of having two old style powerheads blasting direct streams in the tank. He can throw two koralias in there that will provide better water movement for a reef. Not to mention that the koralias will be cheaper and use less power.

I dont want to say CL’s arent useful. I think asthetically they are the best thing you can do for water flow. In a FOWLR, especially BB, with 6 returns it should be very effective and work very well.

DPS - why 2 CL’s? You can accomplish the same thing just as effectively with only one pump. It will save you considerable money. I would look into the sequence dart pump. Very powerful and efficient. Thats what i had on my CL on my 240g FOWLR.

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I used the side hole to feed a closed loop but had the return go over the top.

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[quote=“logans_daddy, post:3, topic:958”]
First, the system isnt closed. Second, in your diagram your returns could siphon your DT if your pump lost power.[/quote]
How about holes drilled at the water level? (i know not closed loop)

Lastly, you shouldnt use gateway valves.
Why not?
.....SCWD......
Whats that?

What are the main benefits of a “closed loop”?

I added another picture, revised of the original (now with arrows!). If everything below the blue line was gone I’d have a “closed loop” right? What if i just say screw a closed loop, but with the suggested setup I would get increased flow throughout the tank and less flow through the sump.

CL_wSump v2.JPG
CL_wSump v2.JPG975×797 34.5 KB

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Lastly, you shouldnt use gateway valves.
Why not?

Because they are more expensive and not the right valve for the application. A gatevalve would be used when you need to make small proportional, incremantal adjustments in water flow. You dont need that for a CL.

.....SCWD......
Whats that?

http://www.marinedepot.com/ps_ViewItem~category~SCWD_Wavemaker___Switching_Current_Water_Director_(Squid)___3_4_inch_Saltwater_Aquarium_Supplies_Wavemakers_External~vendor~3IQ_Ventures~SearchStr~scwd~action~view~idProduct~3Q1111~idCategory~FIWMEW.htm

Nope, still not a closed loop. Even the diagram above the blue line isnt a CL.

Turnover through your tank and turnover through your sump are almost independent of one another. Think of flow in your tank as what your powerheads are rated(or CL pump) and flow through your system(or sump) as what your return pump is rated. Granted, its a little oversimplified, but you get the idea. You can increase one without effecting the other.

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A gatevalve would be used when you need to make small proportional, incremantal adjustments in water flow
Exactly what I was thinking for my application, read below.

Why isn’t whats above the blue line a CL? The tank outlet is plumbed directly to the pump inlet, the pump outlet is plumbed directly to the tank. The pump can run WOT (Wide Open Throttle, excuse the auto reference) and simply recirculate tank water. Is that not a CL?

Turnover through your tank and turnover through your sump are almost independent of one another. Think of flow in your tank as what your powerheads are rated(or CL pump) and flow through your system(or sump) as what your return pump is rated. Granted, its a little oversimplified, but you get the idea. You can increase one without effecting the other.

That is why I added the two gate valves (below the blue line) to control flow in/out of the sump so it was independent of the flow of the pump circulating the tank water.

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[quote=“logans_daddy, post:5, topic:958”]
In a FOWLR you can get away with not using a current switcher. In a reef its kind of pointless. If he has only two returns and he doesnt have the ability to alternate them what good is it? It will be the equivalent of having two old style powerheads blasting direct streams in the tank. He can throw two koralias in there that will provide better water movement for a reef. Not to mention that the koralias will be cheaper and use less power.

I dont want to say CL’s arent useful. I think asthetically they are the best thing you can do for water flow. In a FOWLR, especially BB, with 6 returns it should be very effective and work very well.

DPS - why 2 CL’s? You can accomplish the same thing just as effectively with only one pump. It will save you considerable money. I would look into the sequence dart pump. Very powerful and efficient. Thats what i had on my CL on my 240g FOWLR.[/quote]

I would much rather use some koralia’s then a CL, save you money both when buying the equipment and in the electric bill. I do love the looks of not having any big bulky powerheads in the tank though.

I am really uneducated on CL, I just know the basic concept and how it works. I was going with 2 CL because the layout of the holes in my tank. There on either sides, so I figured 2 pumps. If I can get away with just one and it would be better, then I may do that. What sized pump would you reccommend? I am really looking for a quiet efficient pump, is the dart the best bet? Also what size holes/bulkheads should I have if I will have 4 inputs and six outputs? Thanks.

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Why isn't whats above the blue line a CL? The tank outlet is plumbed directly to the pump inlet, the pump outlet is plumbed directly to the tank. The pump can run WOT (Wide Open Throttle, excuse the auto reference) and simply recirculate tank water. Is that not a CL?

I think your just missing the concept of what a CL is. The CL will have nothing to do with a sump whatsoever. You do not even need a sump to do a CL. Read carefully what i wrote before, i know a pic would be easier but i dont have the time. In your drawing if you pump is turned off you will siphon into your sump all of the water up to the lowest point of your locline returns. You could install checkvalves to prevent it, but the have a very high failrate and they are not needed.

That is why I added the two gate valves (below the blue line) to control flow in/out of the sump so it was independent of the flow of the pump circulating the tank water.

You dont need gateway valves. You should purchase a size appropriate pump(rated for pressure if you utilize a current switcher) and run it wide open. The ballvalves are simply for maintainence purposes. You CL shouldnt add any volume to your system except for the amount contained in the plumbing.

The concept your missing is this. Your drain into your sump and return to your tank is completely independent of your CL. Your CL is just that, closed.

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No. I think your misunderstanding me.

Above the blue line there is no sump. Totally independent. Water out into pump, back into tank. Is that not a CL? I still don’t understand how above the blue line isn’t a CL.

Below the blue line is the sump. I understand that by including the sump, it is no longer a closed loop.

The siphoning out issue can be solved with a hole at the waterline and/or check valves.

Looking at it again I guess the water isn’t going to simply want to come out of the sump unless there was restriction to it simply recirculating. Perhaps a gate valve between the water out of DT and into pump inlet.

Again, I guess I’m not going for a closed loop, but a system that will allow me to independently control flow through the sump and independently control flow around the tank with a single pump. I could do 5x (per hour) turnover through the sump and 5x recirculation. (~800gph pump/75g = 10x, 50% of the flow circulating, 50% through the sump)

13

Nope, no misunderstanding. Above the blue line your drain is T’d for input into your CL pump and input into the sump. The T is above the blueline. Its not a CL. Also, you have a return from yous sump T’d into the input of your pump. The T is above the blueline, it not a CL, not to mention that i can find no reason for the purpose of doing this.

Checkvalves fail. Siphon breaks fail. I have a durso style return on my RR. IT has a locline with a Y with two flare nozzles for my return. There is a siphon break that extends several inches above the water line. It shouldnt siphon, but it did, once. They can fail.

Looking at it again I guess the water isn't going to simply want to come out of the sump unless there was restriction to it simply recirculating. Perhaps a gate valve between the water out of DT and into pump inlet.

Again, I guess I’m not going for a closed loop, but a system that will allow me to independently control flow through the sump and independently control flow around the tank with a single pump. I could do 5x (per hour) turnover through the sump and 5x recirculation. (~800gph pump/75g = 10x, 50% of the flow circulating, 50% through the sump)

Im really not sure what your trying to do. In no way am i passing judgement and saying your ideas wont work. To be perfectly honest, i have taken the time think it through to troubleshoot all potential flaws. What i am suggesting is that your making it WAY more complicated than it should be.

I really dont see the advantages of an “open loop”. You would have to rely on checkvalves and siphon breaks which would be risky.

:TWOCENTS
Im guessing your main motivation is to utilze the holes in your tank? I would do one of two things.

1)Purchase a SWCD and an appropriate size pump. Build a true CL system. For a softie tank you may not need anything else for flow. This might be sufficient. If you need more flow you might have to supplement with powerheads.

2)Plug the holes and purchase some quality powerheads with a wavemaker. They will be more efficient power-wise, and provide more flexibility. You can program all kinds of flow patterns with a basic wavemaker, not to mention that you can simply move your powerheads to change your flow patterns.

I recently sold my tunze 6100, koralia4, and koralia3. I bought a nice wavermaker, three maxijet 1200, 3 MJ mods, and 3 magnet holders for about $250. Im estatic with the results. Not only can i toggle between 1/2 a dozen preprogrammed wavemodes, but i can also move my powerheads to really dial in the flow. Furthermore, if i feel like i want to get a little more out of one or more pumps, all i have to do is swap the prop(that came free with the kit) and i instantly get another 500gph through the powerhead. Very flexible, and efficient.

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The point of the blue line was to cut out the sump section. Work with me here.

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Oh. Then yes, remove 2 out of 3 T’s and add a riser and you have a CL.

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Hmm this SCWD thing looks pretty interesting…

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I have heard that the SCWD sometimes can become stuck/close and not work properly. Only one side will work? I don’t know if that is a common problem or not, but I have seen posts of people having issues. I’d love to try one though.

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Yep, your right.

There was two causes. One was an engineering problem that has been corrected. The company even went so far as to offer free “repair kits” to customers that purchased squids before the problem was resolved. Secondly, i think a lot of problems are caused by people feeding squids with too much or to little water. You need to make sure that your pushing the appropriate amount of water through these things.

I was a little skepitcal at first. I have never owned one personally, but i would install one in the right application.

19

SCWD’s also reduce flow rate. it takes a lot of the energy to make it move. its a flow restrictor. the first diagram is a lot of piping for no extra flow at best. at worst, the drain sucks air and cavitates the pump, reducing flow even more. just use the two drilled holes in the tank for sump return. if you want a CL. make it a hang on back . a sealed pump hosed into two long PVC U-loops that hang over the back of the tank, one pump suctionfrom the tank, the other pump discharge back to the tank. to prime it, just stick a power head into the suction pipe and blow water into the loop , start the CL pump and let it go.

or get a couple maxijets with propeller mod kits for the back corners of the tank. costs less and moves more water with no chance of leaking.

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SCWD's also reduce flow rate. it takes a lot of the energy to make it move. its a flow restrictor.

your absolutely right. however, keep in mind that only one return is on at a time. i cant imagine that the flow rate coming through one return at a time through a squid would be significantly less thatn the flow coming through dual returns on a T without a squid. Its the on/off effect that make these worth it IMO. Since if switched to my mods that are constantly on/off my corals look MUCH happier.