Closed loop manifold design advice

[techreef]

Hi everyone,

I'm finishing up a closed loop system for my 90G AGA RR tank, but have a question for y'all re: where to pipe my return line into the manifold that is sitting on top of my tank. The manifold has 9 T's in it, w/ nozzles made out of 45-degree connectors pushed on to the T's. Water will flow around the manifold, and ideally flow out of each of the 9 'nozzles'. My problem is that the nozzles aren't equally spaced around the perimeter of the tank. The one's along the back side of the tank must accomodate the overflow, so there is a gap between two of the nozzles. Here's a pic.

--WALL OF HOUSE (BACK)--

---T---overflow-----T--------T------|
| |
| |
T T
| |
| |
---T--------T---------T--------T-------

--FRONT OF TANK--

I'd like to connect this manifold with the return line from the pump (Sequence Marlin pump) right next to the T in the upper-left corner of the above pic. Do you think that I'll have uneven flow out of that back row of T's if I plumb the return here? My other option is to run the return line over a little bit and tap into this manifold right in the middle of that back row. Which do you think is better, or will it matter at all? Thanks for any comments/critiques.

 

[techreef]

EDIT: Okay, my drawing isn't showing in the thread the way it looks when I type it out in the reply window. Please just imagine that that second column of vertical elements is moved over to the right, to form the right-hand side of the manifold.

 

[lfjewett]

Water will always take the path of least resistance. Therefore you flow should never be the same at all of your ouputs, the ones closest to your input source will always have a slightly higher flow. Just make sure the hole diameter is small enough so that the whole manifold is pressureized and then water should flow through all of your outputs.

 

[techreef]

Do you mean the holes out of the 9 nozzles, lfjewett? The entire CL is built out of 1" rigid pvc. I could install narrowed nozzels on the T's instead, if need be. I figured the MARLIN pump would be plenty powerful enough, so that I even have a ball valve on the return line in case I need to scale the flow back a little.

 

[lfjewett]

I didn't look up the specs for that pump.. I don't see any problems with your design. Flow won't be 100% even but it will work. I've only worked with manifolds with 4 outputs but the same idea should scale up as long as the input is => the output.

 

[techreef]

thanks. yeah, the world won't stop turning if the flow out of each of these outlets isn't exactly equivalent. I'm just hoping that none of them are really weak, where the water is just dribbling out of 1 or 2 of the nozzles. I'd like to know that some sort of current, weak or strong, will come out of each nozzle. that's why i asked if it would matter where i tie the return line in on my manifold. thanks for your input.

 

[bassnman11]

You can use insert adapters to reduce the diameter of some of the outlets. When you reduce a outlet, you will increase the velocity but reduce the flow. I have 4, 3/4 outlets and use 3/4 x 1/2 reducers in the ones closer to the pump to get more flow out of the farther ones.

 

[techreef]

that's a cool idea bassnman. thanks! when you say "insert adapters," are they different than the normal PVC reduction connectors you see at Lowe's/HD? where did you buy yours at?

 

[p4ck37p1mp]

This looks similar to my manifold, I used 1" PVC and six 1/2" loclines as outlets. This increases pressure as mentioned so all outlets get about equal flow. You can add locline valves also, to fine tune flow at each outlet, something I may do. This way I can reduce flow in some places and allow for more in others (near sps, etc). I also use a Marlin, but from my basement sump as a return / skimmer pump for a beckett. Not sure how return and closed loop will work together. I'd be a little worried with the Marlin that it might be able to out flow your return pump through the manifold and cause back pressure on the return pump and reduce its flow some.

 

[techreef]

Sorry for any confusion w/ the terms "return." This CL is totally separate from my return pump, which is down in a 30G sump/refugium below the tank. The return pump simply pumps straight up into the return nozzles exiting the AGA Megaflow overflow box. The Marlin is simply sucking water out of the display tank, over the tank edge, down to the Marlin pump, and then back up to the manifold. My question was at what spot on the CL manifold (which sits on top of the tank) to connect that Marlin return line on to the manifold, in order to equalize flow to each of the 9 nozzles on the CL manifold.

 

[p4ck37p1mp]

Ah, got it. Much better than the same manifold, was a little unsure as to how that would work out.

I made my manifold around the perimeter, with a pipe over the center brace also connected to the front tube, the inlet from the pump is in the rear center. I figured this would more or less pressurize the front and back equally, which it does.

 

[p4ck37p1mp]

:
................................................................
. + . + .
. . .
.+ . +.
. . .
. + . + .
................................................................

WOW, thats hard to look at. =P

+ = locline 1/2" outlet
: = 1" inlet
. = 1" pipe

 

[p4ck37p1mp]

hehe, ok that doesnt work, formatting gets hosed.

 

[techreef]

LOL! migraine. coming. on.

I think i understand from your description how you have yours running. that's a great design. (connecting the front and back parts w/ a center tube) i wish I had thought of that!