My sand filter won't filter fine silt and pollen!

[haybird]

Hello,
I have fine silt and pollen collecting mostly along the seams of my liner. I have passed the overnight FC test. When I add a little DE my PSI will jump up by 10 in about an hour. When I turn the pump on I notice sand shooting out the returns for a couple seconds.

If I take the filter apart what am I looking for? What are some reasons my filter is not filtering?
It was working fine last year before I had a o-ring replaced. Its four years old and a hayward 200s
sand filter. Thanks for any advice

CYA 30
CH 60
TA90
FC 5
CC 0
TC 5

 

[PoolGuyNJ]

One of four possibilities: Where the up-pipe and multiport meet, cracked up pipe, cracked lateral, loose mating of the top and bottom halves of the multiport. That may be caused by a worn spider gasket or return spring. Have you been turning off the pump before moving the multiport?

Scott

 

[haybird]

Thanks for the reply!! Yes I shut the pump off before I move the multiport, which is not that often just when back washing. The cracks I assume would be obvious to see, what about the matting? Is that something you can tell by looking at it? Or do you need to know what you are looking for?

I was thinking of having a look after I drain the filter and close the pool. Is that as good as time as any? Thanks for your help!!

 

[PoolGuyNJ]

The multiport should be pretty tight to the pipe. You'll feel it having friction where it meets the pipe once the retaining collar is removed.

Scott