If I might ... it depends on number of factors that need to be considered. Firstly, I ran 37 ppm CL using Cal Hypo broadcast directly around the pool when I opened this year with no bleaching of my liner (not saying anyone else should). The instructions on the HTH product say to broadcast it directly in the deep end. I too get some residue on the bottom that the robot picks up but now tend to dissolve it in a bucket first to avoid that. The other factor is how much Calcium is in your water to begin with and what your annual water replacement is. This is true also of CYA. Being in Ontario I have to close my pool for the winter and can count on at least half of the water being replaced every year. So I can run the season without getting to levels that cause problems. Bleach is not the best value for me in my market area or I WOULD use it ... I'm just suggesting that it's not the only option based on the other factors.