I have a concrete pool with a cartridge filter. I am having trouble finding a way to get the dead algae off the bottom after shocking. When I manually vacuum it either goes right back into the water or the filter clogs up after a few minutes and I'm constantly having to clean the filter. I have a Polaris 380 but it just stirs up the algae and it goes right through the bag. I didn't have this issue when I had a pool with a sand filter but I just can't get a grip on this cartridge filter. I have owned a pool for 20 years but this new one has me baffled. I am eventually able to clear it through constant brushing and filtering but this involves constantly cleaning the filter several times a day for days at a time. This seems to wear out my filters and they stop being effective. Is there any type of pool sweep that is effective or a bag out there for the Polaris that is non porous enough to trap the algae? Thanks!