DE in the pool, Hayward plumbing question

[lensmonkey1]

I have been battling a consistent relatively small amount of DE ending up on the bottom of the pool. I vacuum it up, and it shows back up the next day. Visible like a sand beach. It does not seem to accumulate past that point! I checked the "flex air relief assembly" for a tear. It is fine. The stand pipe o-ring looks good, though I bought a replacement for both. The filter fins are relatively new and I cannot find a tear. I see no cracks in the manifold. There is a black L-shaped send pipe I have marked in a picture. It is a little loose. I can twist it with marginal resistance. It does not seem to be removeable to replace an o-ring. It cannot move downward enough (though there is a fin molded in the bottom of the pipe to prevent that and might be snapped off to do so) but it also should have positive pressure. Any Ideas? Could DE be moving through that connection?
Additional information. The pump always starts with a bunch of air going out the returns. When the pump turns off, I hear glug glug of water leaving the filter. But I have seen no evidence of DE flowing out of the skimmer.
Thanks in advance!

 

[Rancho Cost-a-Lotta]

It sounds like you have a leak in your plumbing that's allowing your system to drain back into the pool when the pump is shut off. One common area is the air relief valve on top of the filter. There are O-rings inside of that valve that may fail. The plumbing system should be able to hold pressure. Yours does not. This would explain the air being blown out from the returns when you start the pump.

Try turning off the pump and listening carefully for any hissing sound. As your plumbing drains down, it will suck an air, and you may be able to hear it.

 

[lensmonkey1]

It sounds like you have a leak in your plumbing that's allowing your system to drain back into the pool when the pump is shut off. One common area is the air relief valve on top of the filter. There are O-rings inside of that valve that may fail. The plumbing system should be able to hold pressure. Yours does not. This would explain the air being blown out from the returns when you start the pump.

Try turning off the pump and listening carefully for any hissing sound. As your plumbing drains down, it will suck an air, and you may be able to hear it.

Thanks for the advice. I do hear the water leaving. The air relief valve has been recently replaced, but I will check it and listen at that area. Also love your moniker "Rancho Cost-a-Lotta" ;-)

 

[Rancho Cost-a-Lotta]

I do hear the water leaving

If water is leaving, air is entering. Find out where the air is coming in.