A few years ago I abandoned my swg system and went to manual chlorine application in addition to adding borax. I was elated with the results with Borax. Sparkling water and soft on the eyes. It appeared to reduce algae growth by 80%. That improvement seems to be wearing off. Although theoretically, like in swg systems, the borax and salt will not leave the pool, the question is, will it lose potency and how do I measure it and maintain it.