Where we mention HTH 52037R Pool Shock Advanced Cal-Hypo Formula — 1 lb 12-Pack

• Weekly Pool Care: Your Maintenance Schedule and Checklist

  Weekly oxidation boost · Best for: Cal-hypo shock for breaking down organics and preventing chloramine buildup

• Free Chlorine in Pool Water: What It Is, Ideal Levels, and How to Raise or Lower It

  Cal-hypo shock without added CYA · Best for: A breakpoint or algae-shock branch when calcium hardness and the label dose allow it

• Pool Shock: How to Raise Free Chlorine Safely

  Best overall cal-hypo · Best for: Routine oxidation on chlorine pools; 12-pack covers most backyard doses