Last year, I upgraded from an old dying hayward 1 HP, to a full rated 1 HP Superflo 2 speed. Filter is a stainless steel tank, Heldor Clearflo DE36, might be 15+ years old, with a heldor SP710 multiport valve. Not sure how old the grids in the filter are, but i know they are more than 8 years old. InGround vinyl pool 16x32. With old pump may psi was 15. now with new pump psi is 20-22.
So, on with the problem. Last week, i woke up to a cloudy pool with a bit of light green color. Went to a franchised pool store, tested water and they recommended to shock it. Shocked with filter running for 24hours. Algae dead, brown dust on floor of pool, so I manually vacuumed, and backwashed filter, new DE added. I noticed that DE was lightly flowing into pool through the closest return. I took apart the filter, DE was nicely caked on to the grids, individual grids look fine, no noticeable holes, or tears, except two grids that have a black coloring in the lower 6 inches, which was not there, last year. After assembling the filter i noticed that the O ring on the stand pipe was shot. Thought that this was the problem. So i replaced it. Looked at the multiport spider gasket, it has rounded edges. Is that right? Vacuumed to waste yesterday and did another backwash on filter, added new de. still same problem. Now my filter runs at 15psi, which is strange since for the past few months, its been reading 20/22 psi. this seemed a little high. when it was running at 22psi, you can see the top of the stainless steel filter tank swell up slightly.
Anyway to make a long story short. I took my problems to the expensive local pool professionals in my town. I trust them, they are very reputable. In fact they installed this pool 20 years ago. They have the grids at $28 per grid. That's over $200 for a complete set. Amazon has a complete set of Unicell grids for $86. They also said that it might be time to replace the old ClearFlo with a new 36sq ft Pentair filter for $750. and a new valve for $150. That's going to be $1000 with tax and install labor.
Are they right, should i buy a new filter, or should i just replace the grids and valve spider gasket? Are the Unicell grids any good?
Could the black on the grids be from PhosFree w/Pool Perfect?