Hello, I have a 12,000 gallon pool. Cartridge filer and VS pump. I have kept a free chlorine level of at least 4 but have been seeing algae start growing. Do I need to SLAM if it’s just small amounts of alage? From what I have read about SLAM is that seems it’s for when the water is green and cloudy and clearly needs a mass amounts. My water is clear I can just see the green showing up on the walls.