Return Manifold

[rudeanduncouth]

I just got done implementing a manifold into my 125g. Unfortunately I think I may have made few mistakes that could potentially be costly.

First, I did a basic design running the outside rim of the tank. Basically the same as the illustration seen on your article. After I did some other readings tonight, I found out that I probably shouldn't have used the 90 degree elbows on the corners. Mistake 1.

I am using 1" PVC for this. There are seven outlets. On each outlet I have a 45 elbow. I figure I could change this later if need be. The problem is I am using a MAG 18, and it doesn't seem like there is near enough flow. I have plans for this to be a SPS tank. Mistake 2.

Along with the manifold, I also have two 3/4" return lines that are pumped through a SWCD by a MAG 12. All of theses holes are drilled through the back of the tank. While I could potentially upgrade the MAG 18 to a larger pump, I made a another mistake. I only have two 1.5" overflows. As it is now, I have the MAG 18 turned down slightly to avoid the flushing sound. Mistake 3.

So that is the situation. My first question is how much flow should I want to come out of the outlets? Would replacing the 90's at the corners with 45's or flexible tubing be helpful? What suggestions might you offer to increase the flow?

Thank You

 

[Krish]

I know when I did my DIY closed loop the other day, I replaced a lot of the 45's and 90's and just used flex pvc instead, as well as simply replacing the flare nozzles on my outputs to the straight nozzle and the difference in flow was amazing just coming from a mag950. The elbows especially seem to cause problems. Here's the link if you haven't seen it on how I did it. You'll have to scan through the thread to see the changes. http://www.reeffrontiers.com/forums/showthread.php?t=13588

As for how much flow you should have going through that manifold, not sure with that size plumbing. I know they have calculators to work out these things, but not sure where to find them. Hopefully someone will chme in and post the link.

 

[rudeanduncouth]

Thanks your thread gave me a few idea. It will be a huge pain to do though. Will of course be better in the long run. Will wait for other people to join in before I do anything drastic. You ordered all your parts from premium aquatics? Your comment about being able to spit harder made me laugh because that is about how I feel about mine.

 

[-=dieseldave=-]

Daniel,
Are you running all that flow to the sump or is it a clossed loop?

 

[bc_slc]

yeah, you lost me as well with the 1.5" drains. You are talking about two separate things right? drains to the sump with your mag 12/scwd two outlet return, and a closed loop with a Mag 18 and 7 outlets. You don't mention what the intake will be for the closed loop.

If you don't want to change the pump for the CL, then you could always downsize or cap some of the 7 outlets, that will increase flow. If you want to upsize pumps, then make sure the intake can handle it and keep an eye on the intake size of the pump or you may end up redoing some of your intake plumbing.

If you intend to run 7 outlets and want reasonable flow from them, then in a frictionless system you would need like a 2100gph-3500gph pump (300-500gph per outlet). Your mag 18 is not going to be strong enough to support them all.

 

[rudeanduncouth]

DieselDave: It is running in to the sump through 2 1.5" overflows.

bc_slc: Overflows: 2 1.5" drains Returns: mag 12 through 3/4" pvc running through a SWCD. MAG 18 through 1" pvc with 7 outlets.

Sounds like you understand my setup. So how did you calculate the flow?

 

[-=dieseldave=-]

Daniel,
your 2 1.5'' drains should be able to flow 1200gph each. The flushing sound can me fixed by adjusting the air going into the drain.

I’m getting the impression that you don’t have a closed loop and are running all the flow though your sump(the Mag 12 and the 18) is this correct? If so bad Idea.

 

[rudeanduncouth]

Yeah that is the case. Why is this a bad idea?

 

[reedman]

because you are moving water through the sump faster than the skimmer can process it. You want slower flow through the sump and the big flow from a closed loop (or some other means) in the main tank.

 

[-=dieseldave=-]

I echo what Reedman said, as well as,
1) Noise
2) Micro bubble issues
3) Loss or pump efficiency due to head loss from not having a closed loop
4) Wasting energy
These are just a handful of issues with a system like you have now.

 

[rudeanduncouth]

I don't really have much issue with noise or microbubbles. Head loss I can see, though at the height is goes to it pretty minimal. However, it would eliminate an elbow which would be helpful.

As far as my skimmer is concerned it seems like it is dong a pretty good job. I have never heard of that happneing before. The location of my skimmer makes the flow through it pretty slow though. I am using a EV-180 with a mag 12.

 

[rudeanduncouth]

When use the head loss calc at reef central, I get "Total losses are 10.94 feet of head pressure, or 4.73 PSI. with a flow rate of 760 GPH." Which in theory this sounds good to me, however, I am pretty that it is incorrect. I would assume it that the 760 gph would be out of each exits but maybe that is a fallacious assumption.

EDIT: I am idiot. I was heading home from campus, and I figured that my assumption was definitely flawed. Mathematically that doesn't work. So I will have to think and do some more calculations on a better way to make this work. This may be a dumb question, but if I want to implent my manifold as a closed loop, it wouldn't in theory effect my overflows at all? Also when trying to calculate the expected flow coming out of the exits, should I add in the siphon pipe (the up and down that it will make to reach the inlet of the pump)?

 

[Krish]

Your comment about being able to spit harder made me laugh because that is about how I feel about mine.

LOL...

I had sort of the same idea a while back with using overflows to feed a "closed loop" but found out it wasn't considered a closed loop. IMO, you probably would be better off just using the mag12 as your return from your sump (setup however you wanted the flow setup) and then do an over the tank intake manifold like I did to feed the mag18 for a true closed loop. That way you wouldn't have major flow running through your sump, you wouldn't have 2 pumps sitting in your sump heating up the water and won't have to worry about micro-bubbles or noise coming from the closed loop. About the closed loop affecting your your overflows, it won't at all...Have you ever looked on Melev's reef? He talks about how he setup his closed loop with photos and explains the size plumbing you will need. If you haven't seen it yet, here is the link. HTH http://melevsreef.com/closedloop.html

 

[rudeanduncouth]

I have seen that. I love his website. Very helpful. I am running into a problem now that I realized I made a very expensive mistake. I am trying to find a pump that can put the output that I want. The only ones I can find our Dolphin pumps. I have heard mixed reviews about them. I believe I will need a pump at least in the 5000 gph range and damn, I can't afford that. The basics I have figured out is that any pump I use will be reduced by about 50% due to the plumbing, and with 7 outlets it is a pain. More research time.

 

[-=dieseldave=-]

"This may be a dumb question, but if I want to implent my manifold as a closed loop, it wouldn't in theory effect my overflows at all?"

Other than less flow(mag 18) going to it than you have now you are correct.

"Also when trying to calculate the expected flow coming out of the exits, should I add in the siphon pipe (the up and down that it will make to reach the inlet of the pump)?"

No don't add in the Height(Up and down) only the extra length of the pipe and the elbows.

 

[Krish]

I believe I will need a pump at least in the 5000 gph range

These ones here (Sequence)have always had great things said about them. Check um out.

http://www.premiumaquatics.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=Sequence

 

[rudeanduncouth]

I was just looking at sequence pumps and I have pretty good things about them. It is a little less of a kick in the pants on price, but still a kick in the pants.

 

[jlehigh]

Your learning Daniel. You are getting 760GPH (maybe) divided among the 7inlets, so the flow is there, just not the velocity to make a difference. Like bc_slc mentioned reducing the inlets can help but to drive all 7inlets you will need a VERY big pump. PVC is cheap so you might as well take a do-over on this and oversize the manifold diameter. Dolphin pumps (I like them) typically have a 1.5" or 2" output. I would run 1.5 or 2" pipe if spacially possible then reduce down to 3/4" at the outlet itself. This will maximize the amount of flow you will get from the pump.

I'm not a big fan of this manifold myself as it is difficult to get very efficient use of the pump. You have lots of turns, and outlets all on one line so unless you really max out the throughput of the diamter pipe used there will be flow variance from outlet to outlet.

If this is you return, I would just reccomend getting a preassure rated pump and drive a few penductors, but I know this is a significant and not cheap change. I just really like the flow efficieny this type of return offers since you can maintain reasonably slow sump throughput while creating a ton of in-tank flow.

 

[rudeanduncouth]

I did put a small reducer on my outlets, but I didn't go small enough to make a difference. I saw that with the dolphin pumps they use larger outlets. If I decide to go that route I will probably do that. What is $20 after $300. Though it may take up a large portion of the top of my tank. So if you don't like manifolds what do you suggest?

 

[jlehigh]

I might as well make a recommendation.. An Iwaki70RLT or equivilent Blueline will drive two to three penductors and get you aprox 4000GPH of in-tank movement while turning about 900-1000 GPH through your sump. This is in my experience. These pumps (Sequence, Dolphin, and Iwaki) are much louder by the way so a good sound dampening plan is a good idea..