While my pool is crystal clear due to BBB my filter wasn't. After 3 weeks in the new house decided to tackle the filter. Really didn't appear to be too dirty at first but oh my how much slime had built up between the pleats. Literally spent an hour on the first filter between every pleat and decided I wasn't up to a 4 hour cleaning. Spent probably a total of 2 hours on the rest and pressure dropped 8 psi. Decided my next cleaning will require new filters. They are just too dirty for my liking and if I start with new clean filters I should be able to keep them cleaner than the previous owner.