Filter diagnosis

[Tie Twist]

Hi all, I suspect my sand filter may be channeled or at least not working as well as it should. This is my second full year with the pool. Water is great, everything is fine, but I have a few symptoms that are bugging me. First some background:

Pool is about 25-30 years old. I moved i ntwo years ago. I have no idea if filter is original or not, I replaced pump last year.
Assumption - minimal maintenance has been done, based on previsous owner's way of handling other things with the house.

Here are my symptoms:

1.Filter pressure almost never moves. Last year ran at 15 PSI, this year about 12.5 when filtering, but stays pegged there. I backwash every month or so maybe, give or take anyways, even though Isee no pressure rise. (gauge is not broken)
At times, filter pressure after a backwash would increase by 1 psi AFTER a backwash (opposite if what it should do). this year, it goes unchanged after I backwash.

2. When manually vaccuming, I get some particles returning to the pool throught the jets. Big enough that I can see them, but not a steady stream or anything. After I finsh a lap of vacuuming, there isa new deposit under the returns.

Thinking of opening it up and cleaning, but not sur eI want to tackle that....any thoughts?

Thanks!

 

[Richard320]

Do it! And take pictures all along the way. We need an illustrated how-to.

 

[Tie Twist]

Well I took it all apart and was surprised how clean it was inside. Took the valve apart too, and didn't see any obvious sign of any issues. This filter is original, pushing 30 years. so since I couldn't find a problem, I just bought a new Hayward filter. No longer have dead algae/dirt and debris settling back on the floor 24 hours after I vacuum.