I'm pretty sure I know the answer to this, but just thought I'd ask in case I can save almost $300.
I have a Sta Rite System 3 Cartridge Filter. Clean pressure is 16. We're still on the cartridges that came with the pool 8 years ago, 9th season. Last year was the first time that we ever had to clean during the summer. It's usually only done at closing.
This summer, I cleaned the filters about 3 weeks because the pressure went to 20 after a SLAM (due to the dreaded algae hiding behind the light.) There was lots of dead algae in the cartridges. I did lots and lots of rinsing, but no soaking, and pressure went down to 16.
This week it went up to 20 again, which is super fast for my filter. Nothing that looked like dead algae or anything else in particular. This time I rinsed and then soaked in a combo of Dawn and Pool Life Filter Cleaner. Then I rinsed and soaked again in clean water. Then I rinsed, and rinsed, and rinsed again.
Put the cartridges back in and the pressure started up at 18. It hasn't gone up in 3 days, but I'm thinking I need new cartridges.
Opinions? Is it even worth trying anything else given the age of the cartridges?
In my internet searches, looks like PoolSupplyWorld is cheapest. Anyone have a different, less expensive, supplier? If I limp along with this set until close in late Sept, will I be able to get a significant deal on them in the winter? It isn't worth it to delay purchase to save $5, but if I can save $50, I'd do it.