Return size for back of tank?

fishstix · Aug 14, 2017

I am going to have 2 returns on the back of my tank, both being drilled. What size do you suggest I go with for the holes?

I plan to use loc-line, so I was just thinking of going with a 3/4 bulk head and PVC, the return pump is around 2000 GPH, and it output is 1 1/4, The tank is 220gal Is going to be using 20" synergy overflow box.

First do you think the 3/4 bulk head is going to work? I plan to run 1 1/4 PVC and split it at the top to each return.

Second is the 2000 GPH pump going to be enough, or do I need to get something bigger around 2700-3000 GPH? I have not ordered yet.

Thanks so much

Hitmans reef · Aug 14, 2017

I personally used a 1 1/4 hose barb bulk head it takes 1 1/4 hose and my return pump is also I also teed off but left it 1 1/4" until I got to the top of my bulkhead then it takes 1" pipe until I got to the top of the overflows and split it with a 3/4" T so I have quad returns. My pump runs at 3200 gph but that's before going up and around 90's and being reduced. However even after losing head pressure I have a ton of flow.
As for your return pump size all I have ever heard was to make sure your cycling your tank 5 times and hour. Meaning you need 1100 gal of flow after the head pressure. So your pump IMO is just barely big enough to do the job depending on how far it is to the top of the tank from the sump.
I personally oversized to this pump when I had my 90 gal still just so I didn't have to run it so hard all the time. I run a RO 12000 D.C. Pump which also feeds my sterilizer but it's the only other thing my pump feeds beside my tank which is what the open T is.