Ok, I have an above ground pool with approximately 10000 gallons. I added water from well and has rust, but that isn't the real problem. I just can't seem to get the green out of pool. I have owned this pool 11 years and have not had this much problems. Last year I needed to get a new pump. I have a Sta-rite Cartridge filter. I bought a new hayward promatrix pump with the same 1 hp. This year my filters didn't seam to take out the green so I got a brand new cartridge. The new filter worked and cleaned my green water. Then I was gone and have green pool water again, which I cannot seam to get rid of after shocking this time. Could it be and oversized pump. The pressure is always around 7-8psi. My flow rate for my filter is 56. I cannot find a flow rate for the pump. All chemical levels look good. What to do?