Clean, healthful, sparkling water - that's what a backyard swimming pool is all about. Professional pool maintenance crews can keep a swimming pool clean and its water crystal clear, but they cost a small fortune. Yet many pool owners who try the do-it-yourself approach find themselves plagued by a host of troubles. Cloudy water. Algae sprouting on the pool's walls and bottom. Pumps, pipes, and other equipment that corrode and deteriorate at an alarming...