CPR overflow idea

[forsaken541]

Ok, I have a CPR 90 overflow box on my 90 gal non RR tank. I am planning on putting together an over the top CL system on it powered by a Mag 12. Now based on Reef Centrals Head loss calc if I were to use 3/4" pipe to do the job I would be pushing over the upper limits of my overflow box by about 100 GPH. If I were to take this overflow box and take out thedrain fitting, seal the bottom with another sheet of acrylic and then add another drain fitting could I get an increased amount of flow through it or is the flow through more limited by the leangth of the unit?

I guess my other otion would be to put a 3-way off of the CL line and push the excess back into the sump. Give me your opinions on this and what you would do. I would like to get better flow into my tank and be able to direct it better without the ugly PH's I am using now.
Thanks for your help,
Erik

 

[Kensn]

The flow will be determined by the pipe size and the "comb" lenght where the water comes in. Here is the calculator from here:

http://reefcentral.com/calc/drain.php

 

[Jiddy]

Im not awak enough to follow what your sayin or askin, but i made a CL manifold usin 1" PVC and a Mag12, it works fine for half of my tank. The pro's say its not enough flow, but i have four outlets per manifold and you cant see it from lookin at the side of the tank. (sorry this info was prbably no help, but its a bump!)

-Jiddy

 

[Kensn]

If you are currently using the overflow for your sump with another return pump, you may want to plumb a true closed loop by just using piping to go over the top of the tank for the intakes. Here is an example of what I am refering to.

http://www.melevsreef.com/closedloop.html

No need to max out the overflow, let it do it's job and skim the surface and send it down to the sump and skimmer.

 

[wrightme43]

You can always just put a ball valve in the return line and slow down the flow return to the tank. Then the overflow wont be overloaded and you wont have a flood.

 

[dnjan]

Are you adding a closed loop? or just a bigger (or another) return pump?
A closed loop would not use an overflow box. For the setup you describe, you would just have two pipes going over the top of the tank - the intake for the closed-loop pump, and the return line for the closed loop. Probably some sort of T in the intake line so you could initially prime the pump.