low pump flow

[Wayne S.]

I have a new Sequence 750 pump that is not preforming very well.

I have one on my Nexus that has a great flow. The problem one draws water from a skimmer through a 2" flex hose to the pump that has a priming pot attached. From the pump the water is fed to a waterfall via 2" tubing. Total tubing is 26 feet with a hieght of about 18 inchs. The pump sits just below pond surface level. All conections are well tightened and taped as well to reduce any air getting in the priming pot. The lid to the priming pot is tight but not sealed.

When the pump is plugged in the tubing and priming pot is full of water.

What happens is that the flow starts at around 60% of the other Seuence pump (which is over 3,000 gph) and slowly decreases. After 24 hours the flow has dropped to an estimated 500 - 750 gph and by 48 hours the flow has stopped but the pump is still running. Soon after turning on, air seems to be getting in the priming pot and as the air gradually increase the flow decreases.

Any thoughts on how to get proper, consistant flow?

Wayne S.

[Terri]

... if memory serves the flex pipe is at or just above water level coming out of the skimmer then goes to the pump?
While the pump is below water level this in of itself will not maintain "prime", and that series of sequence pump is not designed to be self-priming... air is getting into the pipe, either through the skimmer at some point or there is a pinhole or two somewhere to allow air in. (Sorry I'm not great with descriptions... hope you get what I mean)

Would it be possible to add a bulkhead fitting to the skimmer box and direct plumb the pipe to the pump so all is well below water level - like the sequence on the Nexus.

I wonder if an airbleed valve would work..?

[Wayne S.]

As it is now, the tubing comes out the side of the skimmer through a hole that's an inch or so above the water level. None of the connections are glued but they are as tight as I could get them.

Adding a bulk head under the water level would help keep things primed but I don't have the equipment to make a good hole in the skimmer box. You know anybody with the tools? (hint, hint)

What is an airbleed value?

Wayne S.

[GregBickal]

Sequence 750 can also clog pretty easy. It doesnt take much. A little hair algae, etc.

[Ian]

If your prime pot/ leaf basket was full of water and pumping water and then slowly declines that tells me that there is an air leak on the suction side. The prime pot/leaf basket lid must be sealed or it will cause this problem. Is there a rubber gasket for the lid? It must be sealed or it will draw in air and cause and air lock at the pump.

[Wayne S.]

Our leaf basket has the rubber gasket. We tightened the lid as much as we can but can't tape it shut as we need to empty the basket every couple days. The coupleling used to attach the tubing from the skimmer to the primming pot is very tight and has tape around it to try to keep the air out.

I'll take it apart again when I get a chance and see what else we can try.

Wayne S.