Closed loop system on a 125 gal tank

andy4499 · Post by **andy4499** » Tue Oct 05, 2004 5:35 am

I am really not sure what a closed loop system is, but I have seen a lot of people using them. I am wondering should I use this type of set up or plumb each pump individually. What are the advantages to using a closed loop system. What do you suggest I use on my 125 gal setup? These are the pumps that I plan to put on it for the intake, 2 reo 2500, and 1 or 2 mag 7’s. I would get one large pump and put on it but I do not have the money for that right now and these are the pumps that I have right now. So any info on how to plumb this tank would help me out a lot.

LoneStar · Post by **LoneStar** » Tue Oct 05, 2004 7:18 am

A closed loop system is simply where the intake to your pump is the same as the return. An example: water is sucked from the display and returned to the display.

The advantage to the closed loop is that the pump always has water in it. It never needs to be primed etc. Another advantage is that the pump will only put as much water back into the display as it takes out so the water level will stay constant (unlike a system where the pump is in the sump).

I personally would not run the pumps that you mentioned in a closed loop (I am sure others opinions will differ) on a tank that size. I would just run those as the return from the sump and save and buy an external bigger pump for the closed loop. I will always try and stick with sequence pumps from now on. I have an ampmaster 3000 wchich is a decent external pump and does not draw much more power than a mag 7. I think you could get the ampmaster 3k for about $240ish. By the time you plumb in the ampmaster, you probably will only get about 2500 g/h at best. Thats about 20X turnover rate and you can do away with all powerheads.

Just my opinion,
Jeremy

Snakeman · Post by **Snakeman** » Tue Oct 05, 2004 8:25 am

I've got a 700 gph external pump on my closed loop and it does great. One thing to consider with a closed loop is that you don't have to worry about head presure because even when the pump is turned off the water in the plumbing will still be as high as the water level in your tank do to the Siphon effect. So you can have 3 feet of plumbing or 10 feet you will still have about the same gph as if you had 0 head pressure. When you have a sump return pump head pressure is a major concern so usually it take a lot bigger pump to move the water up to your display tank. Just remember to put a outlet with a cap or something so you can prime the system for the first time you start it up. After it is primed you can forget about it. You want have to prime it again unless you drain the water out of your tank. If you have a closed loop system that is drilled into your glass you might not even have to prime it. I've got my hanging over the top of my tank so I had to prime it the first time.

andy4499 · Post by **andy4499** » Tue Oct 05, 2004 9:01 am

So will a closed loop work with the 4 pumps (in sump pumps) that I mentioned above, or will I have to have an external pump?

Snakeman · Post by **Snakeman** » Tue Oct 05, 2004 9:15 am

Mag drive pumps say that they can be used externally but I would still get a good external pump. I got one on ebay that was cheap and does a great job. I'll have to look up the name of the pump. On my closed loop I have 4 outlets with a swqd wavemaker and one inlet pipe. I have my pump in a wood box on the floor to cut down on the noise. It gives me more that enough flow. You could try the mag 7 and always change it out later. Just put a cut off valve on both sides of the pump so you can change it out without starting a siphon and flooding your house.

Scott · Post by **Scott** » Tue Oct 05, 2004 6:12 pm

I will reiterate what Jeremy said. Don't use Rio's or Mags on a closed loop. You can find a Gen X PCX40 (this is what I use) or a Little Giant used for good prices. I think the Gen X is a little loud but it is a pressure rated pump. The Sequence and Ampmaster pumps are more but are nearly silent because they are low rpm motors (AM3000 is ~1700 rpm and the Gen X is ~3000 rpm.

I am not sure what you mean about in sump pumps though. I have heard of smaller Mag Drive's being used for closed loops but they are notorious for leaking.

Here is a picture of my plumbing. the closed loop changed a bit. Now I used the two bulkheads in the middle and used hose instead of pvc to reduce vibration and I didn't use the Gen X Mak 5 that is pictured.

Fishfood · Post by **Fishfood** » Fri Oct 08, 2004 8:03 pm

scott, so how much flow do you get out of your closed loop set up like that. Is it a powerful current or just a gentle flow. You know i'm looking into doing the same thing but i don't know if i want to run pvc around the entire top of my tank like that. I'm not sure how i want the return to be set up though. I'm probably going to go with a sequence dart for the closed loop.

Scott · Post by **Scott** » Fri Oct 08, 2004 8:21 pm

I get good flow at each end (3/4 locline) ans gentle current in the middle (1/2 locline). I am only using a 1200 gph pump. If I were to replumb I would do it differently. Probably two 1" outlets on each end in the back for the closed loop and 4 in the middle for return. I was thinking of getting a Dart myself. $179 for 3200 gph is good and they are quiet.

Fishfood · Post by **Fishfood** » Fri Oct 08, 2004 8:34 pm

so do you think that would cause a storm with southdown or similar sand? I guess I would have to spread it out becuase that is a lot of flow. Unfortionatly i'm not going to drill mine so i'll have to go with pvc over the back. I have found some black PVC though so that will help a lot.

Scott · Post by **Scott** » Fri Oct 08, 2004 8:35 pm

if it's a 6 foot tank I would go with the stingray or hammerhead so that you can get good flow all around. That is one reason I opted for a 5 foot tank and next time I will go either with a 120 or 150.

Fishfood · Post by **Fishfood** » Fri Oct 08, 2004 8:41 pm

well i'm going to probably go with a blueline for the return with eductors

Scott · Post by **Scott** » Fri Oct 08, 2004 9:29 pm

Where are you getting the eductors? I don't have any problems with sand storms but with twice as much flow there may be some at first. I can't direct the outlets on the end towards the sand now.

Fishfood · Post by **Fishfood** » Fri Oct 08, 2004 10:03 pm

Scott,

I don't know where i'm going to get them yet. I'll probably hunt the net for them. I have pleanty of time though becuase as of today i still haven't gotten a quote back from a contractor or from my insurance inspector. I'm bettting i'm out of my house for 3+ months.

Brandon · Post by **Brandon** » Fri Oct 08, 2004 10:08 pm

I'm hoping to go with the oceans motions device for my closed loop on my next tank... pretty cool looking device:
http://www.oceansmotions.com/

andy4499 · Post by **andy4499** » Sat Oct 09, 2004 8:47 am

Hey Scott

Would there be a chance that you could come over today or tomorrow to posibly give me some suggestions on my plumbing situation. Give me a call some time 978-4517

thanks