Overflow box problem

[brndfrb]

the tank is what is filling up. We put a durso in the overflow to quiet it. I mean the durso can handle alot more water it just isn't getting enough water. But it is the tank that is filling up.

Does the Durso have a small vent hole drilled in the top end cap? Sometimes it can get too much trapped air which will also slow the flow.

Cheers
Steve

[sumphead]

Yeah we drilled the durso. Basically because he is only running a pump rated at 700 [acronym:7e1a238499="Gallons per hour"]gph[/acronym:7e1a238499] He/we/I would like to see the pump run full flow without being inhibited by the ball valve at all. There seems to me no sense at all in reducing the pump. It would be like buying a Vette that performed like a Pinto. Besides it's not as if it were a MAG24 or something. Supposedly the overflow box was rated at 800gph which I find very hard to believe at 1". My suggestions is to either hit up Premium for a larger overflow or add another u-tube.

R-

[Brad]

The overflow box has two chambers...one in the tank and one outside the tank.
In scenario "A", the tank-side chamber is full (level with the tank water surface). The outside chamber stays low. The return pump continues to pump water into the tank leading to overflow of the tank. This situation, [acronym:05f5209885="By the way"]BTW[/acronym:05f5209885], is one that you should have some sort of protection against (float switch), because it is what occurs should the siphon every clogs or stops (snail in the pipe syndrome).

In scenario "B", the tank-side chamber is lower than the water level of the tank, but the outside chamber fills with water. This would have the effect of slowing or stopping the siphon action, but is a different problem. As a rule, the outside chamber should always have a lower water level than the tank-side chamber. If the outside chamber fills up with water, it slows the siphon and moves you quickly to scenario "A".

Where to attack:

A: the siphon is not strong enough for some reason. It isn't pulling enough water. There may be air trapped in the siphon...or the tube may simply not be large enough to move the volume of water that the return pump is adding.

B: The outflow (to the sump) is not flowing fast enough to keep up with the siphon. The outflow hose could be airlocked or not large enough. Use a VERY large pipe for your outflow. Larger than the diametre of the hole in the bottom of the overflow box. I use plastic sump hose available at Home Depot.