I use TFP with my gunite saltwater pool, and it works great for me. I noticed that my neighbor was struggling, and I thought I would try helping him. He has an 11,000 gallon above ground pool (vinyl I assume), and he uses pucks. His pH was okay, but the chlorine was very low (0.5 ppm). He has a lot of algae, and the CYA is at 70. I know that level is pretty high according to the CYA chart, but I'm hoping it's workable without emptying. I'm not sure that it is unfortunately. I know that he will need to SLAM around 28-30. Will this cause any damage to the liner, if I add the bleach by the return line? I have never worked on a vinyl pool before so I am a bit apprehensive.