Seems like every year I battle an algae problem or pollen, or tree droppings and the cartridge gets ruined. My cartidge is a year old. I recently ended a bout with algae and now the cartridge has a slimey coat of dead algae on it, a grayish slime. The pressure gauge on the filter is showing nearly double the pressure...from a normal 10 lbs up to 18 now. I am now letting it soak in a dish liquid mix overnight. If that doesn't clean it should I try the muriatric acid cleaning ? Replacement cartridges I have seen on the internet for about $120.00. Who has the best prices on them these days ?