The original swimming pool shock designed to boost chlorine levels and kill bacteria and algae for a clean, clear pool. Traditional chlorine products contain cyanuric acid (CYA). When too much CYA builds up, it can cause overstabilization or chlorine lock, and cloud your water. The fast-acting, fast-dissolving Cal Hypo based formula provides chlorination without adding extra CYA for a beautiful sparkle all season. This pool shock is great for all pool types and will not fade your pool liner.