What are Pool Clarifiers?
Pool clarifiers rely on the charge difference in the molecules of the clarifier and the particles floating in the water. They are electrically bound together. Once dissolved in water, there is nothing sticky or gummy to clog a filter.
The routine use of clarifiers generally is an attempt to compensate for poor water chemistry, so should be avoided. Occasional use when opening or to recover from an incident like a dust storm or construction debris is not going to be problematic.
Occasional use of a clarifier is fine. But do not lull yourself into the though of using it weekly or whatever. Repeated cloudy water is most likely from a chemistry imbalance and the likeliest isssue is algae. So just be aware of that.
Repeated use, many pool stores recommend it weekly, will eventually cause a problem in your filter media. Many people use polymeric clarifiers and those will eventually gum up a filter. But using at the start of the season after making sure you are completely clear of any algae and, if necessary, a full and complete SLAM Process has been followed, will not bring immediate harm to the filter media.
Clarifiers are different then flocculents. Clarifiers will cause small particles to clump together so they can be skimmed out and captured by the filter. Flocculents cause larger particles to glue together and fall to the pool floor. Flocculents need to be vacuumed to waste and never to the filter.