Closed Loop advice

[ToeTag77]

So I have a tank I am in the process of setting up.
7ft x 2ft x 2ft.

It has four drilled holes in the bottom that accept a 3/4" bulkhead.
I am building an overflow in the back and drilling more holes for it.

The return pump for the overflow is a Mag24 approx 1600gph.

How do I setup the closed loop? use all four holes on the bottom as returns and drill two more holes for feeding the pumps? Or use two of the holes existing as feed and two as return? If I drill more holes should they be in the bottom or the back? I planned on using two external pumps to run the CL and dont want to use any powerheads in thew tank.

Any advice is appreciated as I have never used a CL system. Thanks!
<a href="http://s448.photobucket.com/albums/qq210/jusbechillin/?action=view&current=2022.jpg" target="_blank"><img src="http://i448.photobucket.com/albums/qq210/jusbechillin/2022.jpg" border="0" alt="Tank"></a>

 

[ADA33]

I would drill one more in the middle and use that as a feed and the four existing ones as the return.
It is very similar to the way my tank is set up.
A Dart pump with 3600gph would work good for the CL.

I would also keep it separate from your overflow. Looks like you will need that drilled also.

 

[ToeTag77]

I was planning on two pumps for CL that way if one fails or clogs the other is good....
What if I drilled two more holes dead center of the tank.....

Imagine if the holes were numbered 1-6 from left to right.

Pump #1
1- return
2- drain
3- return

Pump#2
4- return
5- drain
6- return

That way I have return water split up on both ends of the tank as well as in the middle. Does that make sense?

 

[ADA33]

That makes perfect sense, for the Closed Loop.

Are you going to drill for your overflow to you sump?

 

[ToeTag77]

Yeah check out my build thread Ill post more pics.
http://reefcentral.com/forums/showthread.php?s=&threadid=1516511

 

[ScrubberOTanky]

The ideal closed loop should have more drains than returns. Returns won't clog, drains/intakes will. If it were me I would have 2 drains and 1 return for each closed loop pump, especially since the bulkheads are all the same size. Ideally you would have a 1" drain and a 3/4" return. The best bet is two 1" drains and 1 1" return. Plus you can always split the flow with locline at the return to have more options to direct it. if your one drain clogs, you burn up your pump, with two drains you avoid the issue all together and the suction through them isn't as violent. I have seen sleeping fish get sucked into an intake at night....