ste6168
Well, it starts with the pumps. I set the CL pumps in a wallpaper tray so I could catch any spills during maintenance. Note ball valves and unions, always worth the extra cost up front.
The pumps sit behind the stand on the floor. There's no room under the stand because my sump pretty much takes up every inch under there. No need to worry about the elevation difference as a CL does not see static head only frictional loss in piping so limit elbows and such. The feeds are 1 1/2" pipe (reduced to 1" at the ball valves). the returns are 1".
Because my tank is not drilled for the CLs, I had to do siphon drains over the top of the the tank. As this operates off of a siphon there is really no negative impact to flow. But you need to lay it out so it's a direct drop to the pump and you need to be able to bleed air out of the top of the siphon (those bushings you see were later fitted with 1/4" bleed valves). The two to the right are siphons the one to the left is a return. That double elbow over and down to the manifold does effect flow, but is was necessary to clear other equipment.
Here's the manifold. I have 8 possible outlets one on each end center to the side and six across the front. According to Anthony Calfo you want 300-350 gph per outlet. Right now I have six open and it seems to flow OK, I will probably cut it to 5. This manifold is run by a Pan World XP50X (just over 1150 gph) so I am below the recommended 300 gph of flow, but I think you have to test your set up and make a choice that suits your needs.
Once over the op the return pipe reduces to 3/4" to run the loop around the top of the tank to the outlets.
The second CL runs through a SCWD, 1' from the pump to the SCWD and 1" to the corners of the tank then it uses two 1 1/2" outlets to diffuse the flow a little bit. My thought was to break up the laminar flow from the manifold with the pulsing flow of the SCWD. I think it works. I may make some changes to this CL. It runs on a Mag 9 that adds a lot of heat so I want to change it to another Pan World when time & $ allow. I may change to an OM Squirt at that time, we'll see.
Finally from the front, you can see the Sea Swirl mounted right of center. My Mag 7 return runs through this and it is the reason for many elbows in my manifold run. My though was again to break up laminar flow of the manifold. Again, I think it works but I may change it at some point.
If I had to do it over, I would have drilled the tank for the CLs and drilled the sump for the return to run on an external pump. That ship has sailed for now so here we are.
When gluing the plumbing, take your time and use lots of glue, then wipe inside to remove excess. Leaks even ones that don't leak water suck air and make micro bubbles!!! Ahhhgggg MICRO BUBBLES!!!!!
I hope that helps.
Check out Anthony Calfo's forum there are several very good threads on closed loop manifolds and of course Melve's web site for closed loop set ups in general, good reading there.