Bio Guard Mineral Springs Renewal replenishes lost mineral levels and rejuvenates the Mineral Springs System. It is step 2 in the system. The Mineral Springs System utilizes easy-to-apply minerals and a chlorine generator to produce a chlorine sanitizer. It takes only five minutes a week to maintain - in fact, once you've begun the system, you only have to add the Renewal product once a week. The Mineral Springs System is ideal for pools of any size or surface, pools equipped with any chlorine generator, frequent travelers or vacation-takers, and those looking for the luxuries of a mineral pool.