We went away for 10 days so I left the pool running with a load of pucks in the chlorinator. I set it to about the middle point and hoped for the best. On our return the pucks were about 3/4 gone and the pool had algae. CYA had risen to almost 60 from my usual 40. The pucks really drove up my CYA without even providing the sanitation required in warm weather. Had to drain off about a foot of water to get it back to normal. Pucks aren't useless but if you are away for more than a few days they're not far from it. 3 day SLAMM and everything is back to normal. Message here is to be very wary of pucks. They seem like an easy solution but they lead directly to cloudy water and slimy walls. if I wasn't so used to pristine water I may not have actually noticed the algae bloom until it was much worse. I think many people using pucks really don't know what clean water actually looks like.