What each chemical does, safe handling, and how to fix imbalances.
Your active sanitizer. Kills bacteria, viruses, and algae in the water. 'Free' means it's available to work — not already used up.
Bacteria and algae can grow. Add chlorine shock (cal-hypo) at dusk per the dosage in your analysis. Run the pump overnight.
Can irritate eyes, skin, and lungs. Stop adding chlorine, leave the cover off, run the pump, and let sunlight naturally lower it over 1–2 days. Don't swim above 5 ppm.
Pre-dissolve cal-hypo in a bucket of pool water before adding. Never mix with other chemicals. Add at dusk — sunlight destroys chlorine.