closed loop advice needed

[kpatrick]

I am purchasing an 8ft long 240gallon tank. I am needing to know your advice on the following questions:
1. What size and type of pump would you recommend for a closed loop?
2. Would you run everything over the top of the tank or drill the back of the tank for the closed loop.
3. If drilling the back of the tank is best, how many holes for water going out to the pump, how many holes returning back into the tank?
4. Where is the best place on the back to drill these holes?
Sorry for all the questions but its a lot of $$$ to mess this up!
I will be using a Mag18 for the sump return and some Maxijet 1200 modified as well for flow if that helps on your closed loop pump recommendation. Thanks

 

[kpatrick]

surely someone has a closed loop on their tank and has an opinion about this topic

 

[yerboy]

i had a 7ft long 265 and i used a reeflo dart over the top closed loop and 4 koralia #4s and 2 1200gph return pumps for flow. For a fowlr it was fine for a reef i would easily double the amount of flow.

 

[natclanwy]

I built a closed loop for a 120g tank and I used a Reeflo dart for the CL pump. The dart is rated for 3600gph at 0' of head and in a closed loop your only losses are from friction so if you size your plumbing correctly the flow rate will be relatively close to this value. To give you an idea of what size plumbing you will need and how many returns and drains you will need I would need more information like how much flow are you trying to achieve in your tank, do you want use power heads or do you want to do all of it with the closed loop?
You can run everything over the top, on our build we drilled both the returns and the drains, I had 5- 1" bulkheads with eductors for the returns and 2- 1.5" drains. If I were to do it again I think I would only drill the drains and run the returns over the top through a manifold. The problem with drilling the returns is they may not be in the correct place once you put rock in your tank or if you ever decide to reaquascape. If you run the returns over the top you can build the manifold to fit your rock work after you have it in the tank and if you ever need to make a change you can add or remove pieces to adjust the manifold for the different rock work.
Here are some pictures of the build:

 

[acrylic51]

I agree with drilling for 2 1.5 drains to feed your CL pump....with the Dart though I would drill max and let the pump flow and only reduced down size of pipe as it enters the tank, to get the max flow out of the pump.

 

[veni vidi vici]

I use a Reeflo Dart with a over head return manifold and 2 drilled/bulkhead suction screens.

 

[cranberry]

We used black spa screens as well.

 

[cranberry]

Again... used black spa screen. You can barely see it to the right there. Most everything is behind the rock.