can anyone help me figure out the gph for my overflow

i have 2 external overflows that i got from a friend and am looking to figure out how many GPH they are...is there a formula to figure it out or someone that can help me with it?

1



the inner box is 5 1/2" L x 3 1/2" wide x 6" high....teeth are 1" deep

the outer box is 5 1/2" L x 3 1/2" wide x 8" high

gap between the two boxesis ~2 1/4"

width from the outside edge of the inner box to the outside edge of the outer box is ~ 9 1/4"

drain i believe is 1 1/2" with a foam cover over it

2






in tank box 7 3/4"x 2 3/4"x 6"

outer 7 3/4"x 2 3/4"x 9"

drain is either 1.5 or 1.75"

gap between 2"

total width 7 1/2"

 

There are flow formulas for surface area on the tube. HOwever there are so many variables.

Hook it up to your system.
People often valve the return pump and/or put a circulating bypass back to the return pump to limit the flow to the DT and overflows- IF needed.

NOT a good idea to limit/vavle the returns such as to make them quieter though. This can lead to a tank overflow. If you have a proper high level power cut off in the DT to keep your DT from overflowing- that helps a lot. but then you have to be around to fix the problem and restart the system.

 

not really the problem lol, im trying to trade/sell one to help with funding for my upgrade which will have an internal overflow so not very worried