Why is a clarifier needed? Shouldn’t my filter be keeping my pool clean?

Although your filter can be effective at removing most dirt and small particles from the water, it cannot possibly remove all possible impurities.

Like the screens used on windows, there is a limit as to how much it can and must allow to pass through without becoming a solid surface.

Over time, these tiny particles will accumulate in number and the water's clarity can be adversely affected (cloudy to view, or "dust" particles floating in the water when the light is turned on are common indicators).

To assist the filter in dirt and debris removal, routine use of a clarifier will either chemically cause the particles to attract one another and make them large enough for the filter to handle or create an additional "screen" on top of the filter media to capture more particles as they pass through.