Fwiw, I have a CCP 320 cartridge filter, 320 square feet, which is 30 square meters for 20,000 gallons, 76,000 liters. There are 40 foot, 13 meter, evergreen and other trees and shrubs within a few feet of the pool and 80 foot, 25 meter, pines next door. They rain down pollen, needles, leaves...