yup, another OVERFLOW question

[Ali1]

First off, sorry for crappy pics, camera phone doesn't do justice.

How do i determine what my overflow box can handle in terms of how much it can drain? I bought this overflow box with the return pump as "used" so I have no paper work. My return pump is a MAG5 and it seems like I'm almost restricting the pump completely with the ball valve on the return line to prevent the main tank from overflowing, resulting in little flow. There are no bubbles/gaps in the U-tube. The previous owner said he used no ball valve to restrict the return line, so I'm puzzled how this worked for him. he had the same size tank as I did.


Trivia:

The overflow box is a little different than the average in the sense that the outer box can carry a large capacity of prefiltering, bioballs, etc. Do you think the stacked bioballs in the outer box is reducing the flow that much?


The pump is rated at 500ft at 0 head. There's at least 4ft from the pump to the main tank. Based off the data sheet for the mag5, I would be getting less than 300 GPH from the pump.

Inner Box

Side View of overflow box

Return Line

 

[cozmo]

try taking the scrubbies out of the outer box and see if that helps.

 

[Ali1]

I took a mate's advice and added a second utube, it helped when there's no restriction on the pump, but the water level is still really high and i can't lower the overflow box any lower.

Any other ideas besides taking the scrubbies out. I will attempt that tonight.

 

[cozmo]

what size is the drain line and is there only one?

 

[deeda]

He has an 1.25" pool filter hose.

 

[Ali1]

Yes he is right .only one

 

[Pharaoh]

So you are saying that there is 1 1/4" bulkheads and PVC? Most overflows have a 1" inner diameter U-tube. 1" will flow max of about 600gph. Considering the restrictions you have, it could definitely drop. Keep in mind that the 600 gph is unrestricted vertical flow, you have to account for horizontal flow as well.

 

[Ali1]

What restrictions do i have from the overflow to the sump? At this point, the pool hose just sits in the sump. No piping after the pool hose. It literally just fills up my sump and thats it. I have no biochamber inside my sump, its just a tank with water right now. I'm waiting till I fix this flow problem before adding stuff to the sump