My 25,000 gallon in-ground gunnite pook is now 5 yrs old and has the original washable sta-rite filter cartridges, a large and a small, that I have power washed every 6 months. So they've been washed 10 times now. They still look pretty good, there's some separation and wear and tear on the pleats and the straps have loosened.
How often should I be throwing them away and replacing them? Any good sources for new ones?