Closed Loop Design (how does it look)

[jcheuvront]

This is the design I came up with for my 90gal tank. It is a modified version of the one at http://www.melevsreef.com/ with out the SCWD but I may at one in if I can find them cheap enough.

http://www.monkeynovel.com/images/tank/closedloop01.jpg

I have a mag7 but I think I will need a mag9 for better flow. I might make spray bars for the outlets on the ends.

I'm buying the parts this weekend and will hopefully be able to take pictures when I have it done.

-JC

[LarryW]

The only thng I would do is eliminate some of the "Tee"s by using Spa Flex pvc. It's flexable schd 40 pvc. It give you the ability to make those bends without the pressure of a T.
here's a link where I bought mine.

link (http://www.plumbingsupply.com/spaflex.html)

[Blackgagt1]

where are you at in Downers Grove i'm right in Darien

[steve68]

u can also use 45 deg angles instead of 90 it help's to eliminate the hard bend if u want to use Hard PVC,some reefer's feel safe er with hard plum i would use flex pipe & also make sure on the return pipe that the holes dont get exposed to air keep them under water,im asumeing u have a sump & when power goes out the water will drop ofcourse if u dont u just have to worry about evaporation & yes go with the mag 9.
:beer:

[69vette]

Once the return line is split into 4, the flow will be reduced enough that those 90's aren't going to effect anything.

I have this same setup on my 90 gal. The mag 9.5 is not big enough. Each return is only putting out 150-200 gph. A mag 12 or 18 would be a much better choice.

[jcheuvront]

Thanks for the response. I'm about halfway done. I put the ball valves in so I can try to control the flow/pressure to the different outlets. I also made the outlets female threaded ends I was going to try to heat up a piece of male threaded and squeeze it to create a fanned outlet. I figured this would also increase the flow/pressure becuse it it rescriting the outlet. I've seen this done in several LFS. I'm trying to figure out how to control (get rid of) the scum/slime on top. I don't have any overflow boxes. I figure it may help when I add a skimmer in a few months. Untill then I will just try to point a powerhead twords the surface to create a ripple aggitation.

[mikeo1210]

LarryW- Where could I go to see a picture of that "spa flex" tubing? I checked the link you posted but they apparently don't have pics on their site.

[jcheuvront]

You can get SPA-Flex at Menards.

[thedogofwar]

Had a thought awhile back about closed loops and the T that is there to get the siphon started. I was concerned about possible leak issues causing microbubbles, and just the unsightly pipe protruding upwards behind my tank. couldn't you theoretically not use a T or any other opening and just evacuate the air by slipping an airline up into it, like you do on a U-tube overflow? it'll take a little more sucking to fill the lines, but wouldn't that work ok?

[mikeo1210]

jcheuvront- Menard's?? What's that. I'd like to see a pic of the stuff.

You guys seen this.. http://www.sparklingfloorservice.com/tank/closedloop.html ?

I appologize if someone mentioned it I didn't read the whole thread.

This is more simple but may give you more ideas...

[thedogofwar]

Originally posted by mikeo1210
jcheuvront- Menard's?? What's that. I'd like to see a pic of the stuff.

You guys seen this.. http://www.sparklingfloorservice.com/tank/closedloop.html ?

I appologize if someone mentioned it I didn't read the whole thread.

This is more simple but may give you more ideas...

Menard's is a building supply. It's a Yankee thing. :) They aren't in your area or the south. Home Depot and Lowes have it too.

Thats the CL thats linked to melevsreef, they just made it larger and removed the SCWD.

[mikeo1210]

Thats the CL thats linked to melevsreef, they just made it larger and removed the SCWD. [/B]

Doh :lol: Oh well.. good stuff. I like the idea.

[steve68]

thedogofwar i dont see why u cant do that as long as everything stay's underwater it shoulnt break the siphon once u get all the air out u should be OK :)

[thedogofwar]

Originally posted by steve68
thedogofwar i dont see why u cant do that as long as everything stay's underwater it shoulnt break the siphon once u get all the air out u should be OK :)

Well thats exactly what I was thinking. I was just surprised that I hadn't heard of doing that b4 and I've had a few great ideas that were ruined by something I overlooked. :)
thanks for your thoughts.

[steve68]

yeap this is from melev's reef

Would you make any improvements on this setup, now that it is installed?

Yes. I wouldn't drill any holes in the returns. They are unnecessary. If the unit is powered off, the water has nowhere to go, so back siphoning isn't an issue. Also, I would add another coupling to the inlet, as well as a couple of ball valves after the outlets from the SCWD. That way when you do need to remove the pump for servicing, you can close those valves and keep the water in the return lines, unscrew the two couplings and pump can be cleaned. You could easily remove the SCWD as well if it needed cleaning out (or soaked in vinegar water as part of your maintenance). I would also add a 'T' at the inlet with a ball valve on it, to drain the water in the pump before removal. Here's a drawing of these modifications. When I get around to it on my own unit, I'll make the changes and take a new picture, but for now this will have to suffice.

Do you have to re-prime the pump when the power goes off?

No. The water never leaves the loop, only a little water in the return lines drains due to gravity. When it restarts, only a little air is sucked into the unit and is quickly blown out one side or the other for a few seconds.

[mikeo1210]

Does the pump HAVE to be sitting on a flat surface?

[rdrash]

I just built a closed loop for my 75 had a mag 7 for it. It was way under powered. I couldn't even get flow out of half my outlets. Get a mag12 or better

[mikeo1210]

Is your mag "sitting" on anything? Wondering if it's possible to have it "hang" off the back (or sit on the top edge?) of the tank closer to the water surface.

[rdrash]

It's on a solid surface. I wouldn't want it to just hang there. The weight of the pump might eventually break the fittings loose.

[thedogofwar]

Mike, sounds like you may be thinking about a way to get more out of the pump by positioning. A CL works a little differently and with the exception of pipe friction, head loss only consists of pipe above the water lvl of the tank.

[mikeo1210]

Originally posted by thedogofwar
..with the exception of pipe friction, head loss only consists of pipe above the water lvl of the tank.

Which is very little.. unless you put the pump below your tank in which case you would have to account for a little in the way of head loss. Thanks.

[69vette]

In a closed loop system, there is no head loss, unless, like thedogofwar said, the return pipe runs over the top of the tank. If both pipes are over the top of the tank, or both are through bulkheads, there is NO head pressure, regardless of the position of the pump.

[albinooscar]

How can there be no head loss? You still have to push the water up above the pump and from what I understand that is where head loss comes from.

Ron

[69vette]

Because the weight of the water pushing down in the intake pipe cancels out the weight of the water that the pump is pushing up.

The only loss you'll have is friction from the inside surfaces of the pipes.

[albinooscar]

Are you saying that the weight of 1 intake pipe cancels out the weight of 2 return pipes?

That's 1=2 isn't it?

[xchrisjb]

The volume of water coming through the one intake pipe is split between the two outputs. It's therefore more appropriate to say 1 = 1/2 + 1/2.

That being said, you also have to take into account the losses due to the pipe fittings (elbows, tee's, valves, and such) in addition to the friction losses of the water flowing through the straight lenghts of pipe. Of course, some people combine these types of losses and call them all friction losses, but it's just bookkeeping.

[69vette]

Yes, because you're moving twice as much water through the intake pipe as you are through each return.

In a true closed loop system, all you're doing is circulating water.

[gregmoeck]

is it ok to have 3 - 1/2 holes drilled. One for intake and two for return? All 3 holes are drilled below the surface of the water.

[kstockman]

My only suggestion for your design is the following:

In your drawing, you have an elbow on the return inlet to the pump. I would change that to a T and put on a ball valve with a hose barb connector. This way when you pump breaks down, you can isolate the pump from the system. Once isloated, you can open the ball valve and drain the water out of hte pump section without making a mess.

Believe me you will want this. I recently had to chain out my pump and I have to contain the mess with several towels. It was a real PITA.

Just a thought.

[blawson02]

Just out of curosity, what is the usefulness of putting the tube with the cap (on the intake at the top)? I just put my 1st closed loop together last month and didnt look into designs first....

I am looking to remove the setup anyway to put a sump under the tank and redo the plumbing. Very poor 1st time setup.. I tried to rush it to a weekend.. :mad2:

[kstockman]

His tankis not drilled so he is going over the back edge of the tank. TO start the closed loop, he will need to draw a siphon. Once started it shold not fail. The tube with the cap and holes is the water intake for the pump. He has put the equivavlent of a stariner on the intake to prevent stuff, like fish and snails, from getting sucked into the pump.

I beleive this is waht youa re talking about.

[blawson02]

Yeah that is it. So the top would then be removable to start siphon?

[MiddletonMark]

Just be careful to cut the closed loop pump when doing a water change ... the lowered water level might break the siphon.

I'm doing the same thing this weekend ... a Mag12 CLS on my 58g tank `over the back'. No SCWD, actually only one spray-bar outlet though I'm leaving a T w/ valve in case I decide to add a second outlet [maybe even thru a SCWD].

[sdmike]

Hey plumbing gurus.

Isn't a 3/4" intake going to two 3/4" returns going to limit flow? There's only so much that the pump'll suck thru that tube.

I was just thinking of a 1" or 1.25" intake, but then you have to reduce it down at the pump anyway...

Just a thought.

Mike

[MiddletonMark]

I'm going with 1" intake ... as the `grill' stuff I have for the intake is that size ... reduced down at pump to 3/4" intake.

Out from pump ... going to 1" until it goes over the back ... then down to 3/4 or 1/2" ... need to decide. 3/4" output from pump, but I'd really like to just have 1/2" in the tank [smaller!]

Going to spray bar running along whole back of the tank at the bottom [no DSB here]. Unsure about further outputs... though building in a T w/ valve for that future :D

[blawson02]

IMO, it would only reduce flow with 90°'s and if they were not alternating (w/o a SQWD). The sqwd allows most of the water to pass thru each side ine at a time, with some blowby on the other. It wont cut the rate in half like it would without a SQWD.