HTH 6-Pack 1 lb Pool Care Shock Ultra

The amazing all-in-1 weekly formula in HTH Shock Ultra increases chlorine levels, kills and prevents bacteria and algae, reduces eye and skin irritation, prevents stains from metals, prevents scale, improves filtration and softens water-all with results in 24 hours! Traditional chlorine products contain cyanuric acid (CYA). When too much CYA builds up, it can cause overstabilization or chlorine lock, cloud your water and cause algae growth. The fast-acting, fast-dissolving Cal Hypo based formula in HTH Shock Ultra provides chlorination without adding extra CYA for a beautiful sparkle all season. It's ideal for all pool surfaces and won't fade your liner.