Skip to main content

Pool Chlorine Calculator — UK

Metric by default: grams and mL. mg/L = ppm.

Shock Treatment Calculator

Reason for Shocking

Chlorine Types

Tablets (Trichlor)

Slow-release, convenient. Contains stabilizer. Use in floaters or feeders.

Granular (Cal-Hypo)

Fast-acting, great for shocking. Adds calcium to water.

Liquid Chlorine

Quick results, no residue. Loses strength over time.

When to Shock

  • • Weekly during peak season
  • • After heavy rain or storms
  • • When water is cloudy
  • • After pool parties or heavy use
  • • When you see algae starting
  • • When chlorine smell is strong (chloramines)

Safety Tips

  • • Shock in evening to avoid sun degradation
  • • Run pump for 8+ hours after shocking
  • • Don't swim until chlorine drops below 4 ppm
  • • Never mix different chlorine types
  • • Store in cool, dry place away from moisture