It is true that some localities have outlawed CYA in commercial pools but these pools usually have chlorine feeders and ORP controllers to manage chlorine levels. CYA DOES mess up ORP readings but since you are not using one it becomes a moot point. As far as the dangers of CYA vs. the benefits....The dangers of swimming in a underchlorinated pool are very real and have been well doucmented. The 'dangers' of using CYA are not. To my knowledge there have been no human stuides on the carcinogenic properties of CYA and animal studies have been inconclusive. If I am wrong someone please correct me!