Overflow not draining to specifications

[randy 12]

125 gallon tank, CPR dual 1" overflow (should be 1400 gph), BlueLine 1100 pump (should be about 100 gph at 4.5 head - not including elbows).
Problem - have to turn down pump because it pumps more than the CPR can handle. But according to the specifications of the mfgs of the overflow and pump, the overflow should be able to handle the pump with no problem. We keep having to adjust the flow of the pump because for a while the water level in the tank will be fine and then all of the sudden one day, the main tank is about to overflow. What gives?

 

[kellyd]

do your siphon tubes have air in them. that is the only reason i can think of. maybe you have small bubbles building up in them and stoping the siphon. i have a homemade overflow with a 1'' drain and it is going around 200.

 

[kellyd]

just had another thought. if you are losing your siphon, try blocking off one of the 1'' drains, this will increase the flow through the other one and may suck out the bubbles.
bruce

 

[randy 12]

No air in the syphon tubes. I have an aqualifter hooked up to the top of the overflow so it constantly pulls out air and never loses the syphon.
The only thing I can think of is there are two drains in the overflow and I have the two drain hoses connected by a T. Could that T slow it down that much?

 

[chris17]

Having the T in there would be my guess, cause the T is for that size pipe coming from the over flow, but there are 2, not just 1 , so I would be to guess that the T cant handle that much water flow b/c it is the same size pipe. Did that make sence?? thats just what I think,...............hth

 

[randy 12]

It does make sense. We'll try that and hopefully it will work.
Thanks!

 

[tony detroit]

Anything other than a straight down drop will impede flow, your T is probably the reason.