Hey guys new to the forum. Bought a house with a pool, first time pool owner since 07/19. Used TFP to get an understanding of the basics and bought to Tf-100 kit and told my pool guy that carried over from the previous owner to hit the road. He was only using Chlorine Tabs and my CYA was 130+ plus a bunch of other issues like high PH and the DE filter looking like it had never been cleaned. The issue I have now is at the water line and about 1-2 inches above it which is sort of a discoloration like very mild calcium deposit. My pool has about 3-4 inches of wall when the water is at the appropriate height. When I was in Maui last summer I watched the pool guy who was very thorough and when he brushed the edge of the waterline with the brush he poured some sort of cleaning soap or detergent onto the bristles before the scrubbing. I brush every week but I feel like its ineffective just brushing pool water onto the walls. The water line of this pool was immaculate and I kick myself everyday for not asking him was product he was using. I did some research online to see if such product was available and could not see anything at all. Do you guys use any kind of detergent when scrubbing the water line and if so which one? Thank you.