Closed Loop Returns?

[volunteerg]

I am planning on doing a closed loop with a scwd on my 75 reef...tired of the powerheads in the tank.
With a 1" drain and 3/4" returns and running a mag 7 possibly 9.5 pump.
Anyone know if I can get 4 outlets on the top 4 corners of the tank for flow? Seems like I only see closed loops with 2 outlets.

 

[gnorman]

im going to be doing the plumbing on our 150 gallon tank. we're going to try to do a closed loop with 4 returns. we are going to be using the dolphin 5600/4700 for the main pump. it pumps around 20 feet high or so. hope its strong enough to handle 4 returns in each corner

 

[volunteerg]

I guess my question is how to make the flow to all 4 returns fairly equal without running 4 individual lines back.

 

[saltn00b]

to have equal flow you need to have a manifold, basically a loop at the top of the tank with tee'd outlets. I am about to drill for my 150 tomorrow, and will be adding a Sequence Barracuda most likely to it.

 

[volunteerg]

anyone have a pic of a manifold?

 

[my way]

I think you would be better with only 2 properly placed outlets from the SCWD. SCWD's do reduce your flow quite a bit, to add Tee's and more 90's to it will only slow it down more. I recently plumbed a 75 for a friend, I split the return, one side going to a spray bar along the bottom back wall, blowing forward (to keep the sand clean) and the other side goes through a SCWD in each upper back corner aimed to the center of the front of the tank. The pump is a Mag 12 and there are just enough areas of low flow for the corals that like low flow, the rest has a good amount of flow for the corals that need high flow.

 

[volunteerg]

Good idea on splitting the return...I hadn't thought about that option...I 'm not sure about the spray bar though. What size pipe did you use for the overflow?

 

[joncat24]

I don't understand what u r saying about an overflow??? A closed system merely pulls water from the main tank and pumps it back in different areas. It doesnt go to your sump or fuge like your regular overflows do. I have mine set up to draw out of the tank ---through a mag 7--- then into a scwd----the off to two sets of double loc line returns. which gives me 4 directable returns switching intermittently into my display tank.....hope this helps
goto melevs reef dot com and search closed loop

 

[volunteerg]

My understanding is if your drain line into the pump is pulling 600 gallons, the pump will only be able to then push back up 600 gallons into the tank. The larger the drain line, the more flow, hence greater flow within the tank.
Am I on the right track?

 

[my way]

Originally Posted by volunteerg
My understanding is if your drain line into the pump is pulling 600 gallons, the pump will only be able to then push back up 600 gallons into the tank. The larger the drain line, the more flow, hence greater flow within the tank.
Am I on the right track?
That equation works on sumps. A closed loop has no "head" to it. Whatever your pump is rated for is what it will pump, minus restrictions from elbows and the size of the pipe used and the SCWD.

 

[volunteerg]

a ha! that makes much more sense now..thank you!

 

[saltn00b]

my way - what do you mean that in CLS there are no heads and that the pump GPH is exactly what you get? how sure are you about this? doesnt the pump still have to pump water up and fight gravity, etc etc?

 

[slugg3r]

In a Closed loop the gravity pulling on the water entering the pump cancels out the gravity pulling on the water exiting the pump creating a theoretical zero head. That is why in a Closed Loop when the pump turns off the water doesn't flow in either direction.
It won't be exact but you can assume zero head minus the changes for 90 degree bends, etc.

 

[my way]

What he said^^^^^^^^^^^^^^^^^
If you think about it, its basically the same as putting a powerhead in the tank with some plumbing attached to it.

 

[saltn00b]

cool - i didnt know that