I noticed some buildup on the bottom of the pool yesterday and snapped some pictures. My chlorine level has remained relatively high all winter and water has been crystal clear. I would see some build up on the bottom after about a weeks time and just assume it's dirt. I'd run the dolphin weekly and never really see anything but some sand, teeny worms, and small debris. I also brushed about once a week to remove what dolphin missed and just go around the pool. Water has been, and is still crystal clear, but now today, there is a lot of build up on the bottom. Do I need to slam again already? Last year I slammed in August and then again in November. I have slowly let the chlorine numbers come down since I last slammed in October. I removed my SWCG in November and reinstalled it this weekend since our temps have started coming up a bit. I only seem to keep the build up away on the bottom when I slam and then when it comes down to normal levels, I get this build up again. I just don't understand what I am missing?