I have a 25000 gallon inground pool with a vinyl liner and a hayward pro series plus sand filter.
We often have problems keeping the pool clear. Recently we had to shut off the filter for 24 hours after we added some kind of algae killer and a bunch off white residue had to be vacumed out of the pool. Now we seem to have some green dust on the liner that we can brush off but it seems to be floating in the water and the filter does not seem to clean it out. we just replaced the sand just in case there was a issue with parts broken in the filter and i could not see anything wrong when i replaced the sand. We use the 3" tablets in the skimmer basket and have a test kit i can post numbers tomorrow.