Dirt through filter?

[Dent]

So I have struggled with this pool for the last couple years trying to get it clean and throwing all kinds of chemicals at it. This year I purchased a slime bag. And noticed that inside the slime bag I was getting large pieces of plant garbage. So how is this stuff getting all the way through my sand filter? I even had my kids send some dirt/plant matter into the skimmer, and put a sock on the return. After only 90 seconds I can see pieces that they had sent down the skimmer.

I checked the multi port valve and from what I can tell it looks ok. It doesn't leak and there's no water coming out the backwash line. I've checked my sand and it looks good. How is this stuff getting through?

I'm about to purchase a new filter, but I don't know what's wrong with my current one.

Any suggestions please? Any other tests I can do? Pictures you'd like to see?

 

[cowboycasey]

Welcome to TFP

you need a deep clean Here ya go

Deep Cleaning a Sand Filter

 

[Dent]

I tried this last year. Same video I followed last year too. I can do it again but I don't understand how large pieces of plant matter is getting all the way through. I really thought it would be my valve not sealing. But then why isn't it pushing water out the backwash line.

 

[Texas Splash]

Odd. That would almost sound like your multiport valve was stuck on recirculate (internally). At least that's the symptom you seem to be describing if you can actually drop something into the skimmer and are sure you see the same thing come back a minute or two later and not get caught in the pump strainer basket. But you've not seen any other "internal" indications of something wrong with the multiport valve (sand, etc)? You're positive the debris blowing back into the pool's return jets is the same stuff you're adding to the skimmer?

 

[Dent]

I'm not positive it's the same stuff. Just that I add some plant junk into the skimmer and then catch similar stuff out the return. I have 3 returns and I'm only putting a sock on one. if I put the multiport to recirc my pressure goes to 0. With it on filter I get reading about 5.