Sump return GPH question

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Aquarium Advice FINatic
Sep 24, 2003
Wilmington, North Carolina
I am converting an old 20 gallon tank into a sump for my 29 bowfront and have a free 740 GPH pump for the return. Anyone know if this will produce to much power or if it is ok? Any help is appreciated!
If you are putting the sump below the tank I and having it return the water at about 4 to 5' I don't think that will be too much flow.
I should have about 4' easy and it will also have to have a few tight bends as well so I thought it would be fine but wanted to ask the experts to get your take!
As long as you overflow is rated for what the pump will be supplying at the head height, you will be fine.

On my frag system, I have a 1" bulkhead. It will max out with a Mag7 at about 3 ft of head.
ive got a pump thats 780 gph, an overflow box rated 600 gph on a 29 gal, the head is about 3-4 ft, and i way overshot. the pump is too much, i had to get a ball valve to accomidate. its alright tho, better too much and tone it down, then not enough at all!
Vsn I think that I will be in the same boat. I will have a few bends in the return and also will be "t"ing off the returns into the tank to 2 seperate exits so Im hoping that it will slow down the flow enough that I dont have to explore the other options. How much of a problem was the ball valve to install? Im bouncing between buying a lesser GPH pump or setting up the ball valve if needed. Thanks for the help!
Definitely go w/ a ball valve. Just "T" it off back into the sump(you can see a pic in my gallery) so you don't burn the pump out prematurely. As vsnsofadrgn said, better to have to decrease the flow some. With time, as corals grow and block water, you will most likely using the extra flow eventually.
I had the same problem. I added some elbows and a Tee to split the return going to the two pumps. I also added another Tee to send flow into the fuge and back go the sump.
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