We had a saltwater system, but when it took a dump last summer, I decided to go straight chlorine (old school). I bought a floater with tablets and shock and I was on my way. Over time I did not keep my end of this deal, and I was not keeping an eye on the chemicals. I would test the water and would only add chlorine or acid as needed, but I did not test for other chemicals that can cause problems. Yellow algae started and I started to treat this issue, but it always came back. So last weekend we decided to drain the pool water and start over with a better plan of keeping a better eye on the chemicals. For piece of mind I asked a pool supply house how to treat the walls where the yellow algae accumulated. He stated that the algae is dead, however, if it will make you feel better get a 2:1 ratio of chlorine and water and just pore it on the walls. We did this and washed it off with the hose and started to see some staining, I thought that maybe when the pool is filled that the stains would fade, they have not. I also saw white stains on the steps and in front of the skimmer. A pool surface company was hired to bead blast the calcuim waterline off our tile. The company told me that the white stain on the steps and in front of the skimmer were from the floater and chlorine tablets. This company suggested a no drain acid wash for the stains from the 2:1 chlorine/water wash. They said it might work but not sure if I should. The pool surface is a 3M plaster/pebbles. i have seen other chemicals for stains that seem easier to handle, what would you suggest.