Closed Loop System Problems - Please help!

[ReefWhatYouSow]

I'm hoping that everyone can help me out. I am trying to set up a closed loop system on my tank that will pull water out of the corner of my tank and push it through pipes that I have built into the rock wall that surrounds my overflow. There are holes that were drilled into the pvc pipes prior to the rock wall being built.

Is it because I have the pump sucking the water up?

I primed the pump prior to using it (or at least I thought I did?)

Thanks for the help!

http://i1371.photobucket.com/albums/ag286/nathanandrewwilsonreefwhatyousow/DSC_0626_zps9394651e.jpg

http://i1371.photobucket.com/albums/ag286/nathanandrewwilsonreefwhatyousow/DSC_0627_zpsd8c79d16.jpg

http://i1371.photobucket.com/albums/ag286/nathanandrewwilsonreefwhatyousow/DSC_0629_zps9f5d99c1.jpg

http://i1371.photobucket.com/albums/ag286/nathanandrewwilsonreefwhatyousow/DSC_0628_zps8ed0d3ab.jpg

[Gorgok]

I'm not sure what your problem is, though i guess you are not pumping water? If you do manage to prime it (remember it will drain down both lines...) it would still scare me to use that pump out of the water. The weak seal between the body/volute could end up spraying water all over the place. Then you will still lose prime whenever shut down.

On a pump higher than water level you should use a self priming pump.

[mcgyvr]

horrible setup.. expect problems.
Pumps should be gravity fed water.. They push not pull.

Time for a redo... sorry try again

[uncleof6]

It takes some engineering know how to use a centrifugal pump to lift water. Not done right, (the math, engineering) you end up killing the flow on the intake, and getting "nothing" at the output. in the interest of not doing a physics or engineering lecture, I will just throw some of the terms out there: Net Suction Head Pressure Available, and Net Suction Head Pressure Required. Do yourself a favor and put the pump under the tank. With the pump under the tank, the only variable you deal with is friction loss, (with a closed loop) and the "lift," commonly called "head height," "pressure head," or "head pressure," will be zero.

One thing you need is called a foot valve, to maintain the prime. Size of the pipe is also critical, and the math is not exactly simple, though doable. I can tell you one thing: with that small pipe, it is a no go. Since closed loops are not efficient in creating the end result with is not gph, rather vertical mixing, and inflexible, 90% of the time it is more advantageous to bite the bullet and use power heads.

[ReefWhatYouSow]

It takes some engineering know how to use a centrifugal pump to lift water. Not done right, (the math, engineering) you end up killing the flow on the intake, and getting "nothing" at the output. in the interest of not doing a physics or engineering lecture, I will just throw some of the terms out there: Net Suction Head Pressure Available, and Net Suction Head Pressure Required. Do yourself a favor and put the pump under the tank. With the pump under the tank, the only variable you deal with is friction loss, (with a closed loop) and the "lift," commonly called "head height," "pressure head," or "head pressure," will be zero.

One thing you need is called a foot valve, to maintain the prime. Size of the pipe is also critical, and the math is not exactly simple, though doable. I can tell you one thing: with that small pipe, it is a no go. Since closed loops are not efficient in creating the end result with is not gph, rather vertical mixing, and inflexible, 90% of the time it is more advantageous to bite the bullet and use power heads.


Hey uncleof6! Thanks for your thorough explanation of closed loops. I'm going to do some more research into the areas that you mentioned. Just so you have a better idea of what I am working with here is a link to my build thread:

http://www.reefcentral.com/forums/showthread.php?p=23411685#post23411685

I'm using two Jebao RW15s but I was hoping for some more random flow by hooking up this closed loop system (variable speed pump) to the Apex. The closed loop is just a bonus and not the overall flow.

Would it be okay to put it in the tank with screen? It would still be sucking from the same tank that the water is exiting into.

[uncleof6]

It would not be my first choice....

[1234]

This is the backside of my old 80gal cube, the returns are in the corners thru the foam rock wall , the 2 big 2" PVC near the center bottom is the intake for the Sequence 4500 pump that I had for the CL, which sat on the floor behind the stand. The reason that I went with 2x 2" BH's was to softened the suction of the pump so I would not have spaghetti "nems". On top of the pump I had a Hayward 3 way ball valve turned by a 1 rpm motor so the flow got switched from one side to the other. Worked great, cheaper than an oceans motion and the valve was free.
http://i48.photobucket.com/albums/f230/wanareef/rear-tank-stand.jpg (http://s48.photobucket.com/user/wanareef/media/rear-tank-stand.jpg.html)
So your setup will never work right, you need a big pump or more PH's

[ReefWhatYouSow]

This is the backside of my old 80gal cube, the returns are in the corners thru the foam rock wall , the 2 big 2" PVC near the center bottom is the intake for the Sequence 4500 pump that I had for the CL, which sat on the floor behind the stand. The reason that I went with 2x 2" BH's was to softened the suction of the pump so I would not have spaghetti "nems". On top of the pump I had a Hayward 3 way ball valve turned by a 1 rpm motor so the flow got switched from one side to the other. Worked great, cheaper than an oceans motion and the valve was free.

http://i48.photobucket.com/albums/f230/wanareef/rear-tank-stand.jpg (http://s48.photobucket.com/user/wanareef/media/rear-tank-stand.jpg.html)

So your setup will never work right, you need a big pump or more PH's



Thanks for sharing your setup. The pic definitely helps some. I'm guessing it's not my pump size since I have a Jebao 9000 variable speed pump. It has to be that I have been trying to force it to drink out of a straw.

I could always stick it in the sump but that isn't technically a closed loop system as air can easily enter.

Any other ideas on how I can make it work? Too late to drill any holes in the tank.

[ReefWhatYouSow]

It would not be my first choice....



This is the backside of my old 80gal cube, the returns are in the corners thru the foam rock wall , the 2 big 2" PVC near the center bottom is the intake for the Sequence 4500 pump that I had for the CL, which sat on the floor behind the stand. The reason that I went with 2x 2" BH's was to softened the suction of the pump so I would not have spaghetti "nems". On top of the pump I had a Hayward 3 way ball valve turned by a 1 rpm motor so the flow got switched from one side to the other. Worked great, cheaper than an oceans motion and the valve was free.

http://i48.photobucket.com/albums/f230/wanareef/rear-tank-stand.jpg (http://s48.photobucket.com/user/wanareef/media/rear-tank-stand.jpg.html)

So your setup will never work right, you need a big pump or more PH's


Can you all tell me why it wouldn't be advised to put the pump in the tank? I also have a frag tank next to the DT. Would it be an option to put it in there. Of course I would have to adjust the flow of my tanks to compensate.

Thanks again for all of your help! If we can make it work, I would like to do it.

[Dapg8gt]

Thats definitely not going to work sorry buddy. Like others said it would have to be a self priming pump and even then the way it's configured makes it basically useless. I don't think adding the pump to the tank is going to change much as the pump is plumbed with such small piping it's nowhere near the advertised flow rates and it's less than ideal in multiple ways.

Time to rethink the plan and ditch the idea imo, look at other closed loop systems to get a grasp on why yours won't work. It's run backwards, the inlet/exit piping is to small and the pump needs to be mounted below the tank with a suitable pump for external use ( the Jebao isn't one of them).

[Markilles]

It would work as long as your pump is below the water line as long as you have it primed it would work the same way as a canister filter minus the filter priming it might be a bit of a pain though if it'd hard plumbed to the bottom

[ReefWhatYouSow]

The sad realization is that is not going to work and maybe I could have done things different 6 months ago when I made the rock wall but no going back now. Maybe I can send pods down the tube and the can come out of the cave of pipes in the rock work lol...

Does this also mean that I will have problems pumping water from my garage into the ceiling and over to the fish room for water changes?

[Gorgok]

Does this also mean that I will have problems pumping water from my garage into the ceiling and over to the fish room for water changes?

Assuming your pump isn't above the waterline of that setup, probably not. It will have some head to work against (pipe height - waterline) but many pumps can handle that...

[Dapg8gt]

All pumps have a flow chart with a max head volume they can pump.. Just make sure the height is not higher than that first. Then take the total run length from that high point and plug it into a head loss calculator or do the math to see if the pump can handle it.. It also accounts for all the fittings you used for the gallons per hour it's going to pump.

Juat search pump head loss calculator online, I believe RC has one also.

[ReefWhatYouSow]

All pumps have a flow chart with a max head volume they can pump.. Just make sure the height is not higher than that first. Then take the total run length from that high point and plug it into a head loss calculator or do the math to see if the pump can handle it.. It also accounts for all the fittings you used for the gallons per hour it's going to pump.

Juat search pump head loss calculator online, I believe RC has one also.


Thanks so much for directing me that way. I checked it out and it looks like I'll be good with the Mag9.

[uncleof6]

Thanks so much for directing me that way. I checked it out and it looks like I'll be good with the Mag9.

Provided, you use 1.5" pipe on the outlet, and the pump is lower than the water it will pump. The 1.5" pipe is so you get flow out of it, (in the instructions for the pump) and the location is from prior posts.

Honestly, the Mag drive pumps are antiquated, and poorly designed. Danner has not updated/upgraded their designs, and from all appearances are not going to. Modern pumps flow more, with less energy consumption and hence a lower heat generation. Mag drives are just noisy water heaters, with poor actual flow performance.

Flow calculators are great is you like under pumping systems, as the problem needs to be approached with the pump and unknown, and the flow rate a constant. A pump that can do the required job is chosen, not trying to figure out what a pump will do in a given circumstance. This is the reason folks really do not have a good idea of what their system is actually flowing.

Most hobbyists approach this from a "guess" point of view, but designing a system with a bit more engineering point of view, will give better results.