16x32 IG Vinyl Pool. I had issues last year with my cartridge filter passing debris back into the pool while vacuuming. I bought new cartridges, but nothing seemed to help. My 3/4HP pump motor was making lots of noise, and sometimes required a smack to get it going, so I just purchased and installed a Hayward 1HP 2-Speed Super pump, along with a new Hayward C1200 cartridge filter. I am having the same problems with the new setup. Every time I try to vacuum the dead algae off the bottom, it just gets blown back into the pool again. Am I doing something wrong? Is it possible to add some D.E. to my cartridge filter? Any help would be appreciated.