[Josh24]

Thanks Mark.

I don't intend to use a traditional over flow but rather 2 - 2" 90 degree PVC pipes. 1 will feed the sump the other will feed the closed loop. Does anyone see this as being a problem?

This is what Reef Central calculator provided for the Sump Return
Using the following input parameters
Gallons per Hour = 2100

Drain and Overflow sizes are calculated as
Recommended minimum drain pipe diameter = 1.89 inches
Recommended minimum linear overflow size = 32 inches

This is what the Reef Central calculator provided for the Closed Loop Return
Using the following input parameters
Gallons per Hour = 920

Drain and Overflow sizes are calculated as
Recommended minimum drain pipe diameter = 1.25 inches
Recommended minimum linear overflow size = 14 inches

This seems werid as Im using the same type of pump for both the closed loop & the sump return and the GPH is extremely different. Can anyone explain why that is?