Gravity flow rates

[Anonymous]

A short time ago, someone posted the gravity flow rate for different size pvc pipe. I have searched but I cannot find it. In particular, I am plannig on setting up an Oceanic 200 that is pre-drilled with a pair of 1" drains and a pair of 3/4" returns. The max flow rate is purportedly 1400 gph (700 gph for each 1" drain). To increase the turn-over rate, I was thinking of using the 3/4" returns as additional drains. I would then run the returns up over the back. What would the total flow rate be for this set-up. Thanks in advance.

 

[Anonymous]

We have an Oceanic 200. I took an 1 1/4" tee that was threaded on all three sides. I screwed two 1" MPT to barb fittings into the tee and one 1 1/4" MPT to barb fitting into the tee. I then screwed a 1" MPT to barb fitting in the bottom of the bulkhead fitting in the bottom of the tank. I then ran 1" vinyl hose from these to the tee and 1 1/4" hose from the tee to the sump. A pictue of this would have saved me a lot of words here and if you want one email me. I do not know what the rating of this is in GPH but we run an Iwaki RLT100 (2000 GPH) pump for a return and the drain works fine. The flow out of the 1 1/4" hose looks like you could put a fire out with it.

 

[Anonymous]

Just considering the cross- section of the drains, the additional flow through both 3/4 inch should be about 800gph(400 each) for a total of 2200 gph.

 

[Anonymous]

Aquaman, if I understand your set-up correctly, you split the 1" drain (from the tank bilkhead) into 2x 1.25" drains. The 2x 1.25" drains then take the water to your sump. I also assume that you have this set-up at both ends of the tank. It also sounds like each set-up can handle 1000gph. Let me know if I have got this wrong.