plumbing Question

I am running 2 dual drain overflows rated for 1200 GPH each. That in theory means 2400 GPH draining to my sump. My return pump is the Mag 2400. In theory im am draining 2400 GPH and returning 2400GPH. I have multiple 90 Degree fittings in the return line, to include a check valve and a ball valve. All this should create less flow and greater head pressure. I am using 1" pipe for everything. The problem is even with 12, 90 degree elbows in the return plumbing, i have to cut my pump back almost halfway with the ball valve or the tank overflows. Would making the return plumbing with 2" vs the 1" fix this problem? I want the high flow rate, as this is a 300 gallon tank with agressive fish. { triggers, groupers....} Why does 2400GPH drain slower then 2400GPH returned restricted with 12 , 90 degree fittings? Is it becasue the gravity drain, vs pump pressure?

 

Yes, You can't get a 1200 gph on your drain overflows using 1" pvc. It will have to be larger, although the exact size I cannot say... I just know that gravity draining water through a 1" pipe cannot get much higher than 600 gph.
Hopefully someone else with the exact numbers will chime in and let you know

Jim

 

Working on cross sectional area of the pipe sizes, 1" pipe has an area of 490mm,
1 1/4" has an area of 804mm, 1 1/2" has an area of 1257mm so increasing the drain pipe sizes to 2" will give an area of 1964mm per drain, 4 times what you have at the moment and should be well plenty.

 

plumbing

I have 1200 GPH per overflow box due to the fact that each oveflow box has two 1" drains, 1" drain should flow 600 gph. So I have four 1" drains leading to my sump. I understand the a single 2" pipe will flow more water then two 1" pipes. The problem is with Twelve 90 degree fittings in my return line and 2 valves ( check and ball) I thought with that much head pressure My Mag 2400 should do the job. I even used the Calculator on Reef Central to figure my flow lost due to the height and restrictive fittings, should be a big enough amount of head pressure to use the mag 2400. So What is my next move so i dont have to close the valve over my pump half way?? I cant change the overflow boxes. Four 1" drains should be plenty for a 300 gal aquarium. Someone please help.
I also sent Bob Fenner an message, if he answers i will post it. Thank you

 

They may flow that much while under pressure but there is very little pressure from 2" of water column (head) on top of the 1" lines. You either have to go with larger lines to your sump or put a tee in the discharge of your pump to return a portion of your water from your pump back into the sump. (suction side of the pump). This will reduce the flow to your tank without throttling back on the pump.

Jim

 

with agressive fish why are you looking for that much flow anyways. I understand the exercise and all but that can be produced by PH and CLS. With a fish only you don't need that much turn over.

 

plumbing

Its fish only for now, and i dont want to see anything in the tank IE.. powerheads. My 72 bowfront reef turns over 19 times an hour and Its really a good thing. All the corals must enjoy it because monthly i am fragging corals and giving them to some local reefers. Just seems like with the higher turnover everything in the tank beneifits. And the 300 will be my reef very soon as my 72 has outgrown itself.

 

If you have any air in your overflows thats also going to drasticaly cut down on the flow they can handle