Brand: EF-Chlor / Aquatabs NaDCC % Chlorine: 60% available chlorine - 1.67g gives 1g chlorine. 4g = 2.4g chlorine. 1. Shock Cleaning - Leftover water in tank If Sintex tank has 50L old water left: 8.3g in 50L = 100 ppm Contact: 30 min, scrub walls, drain full 50L. Don't drink. Wear gloves. 2. Full Tank Drinking Water 1000L tank fills in 20 min = 50L per min. Normal borewell: 3.3g per 1000L = 2 ppm Dirty / after cleaning: 8.3g per 1000L = 5 ppm max 4g in 1000L = 2.4 ppm - safe daily dose Contact Time: Always 30 min AFTER tank is full before drinking / cooking. Last water needs 30 min. For RO: 2 ppm water wait 30 min, then run RO. 5 ppm water wait 2-4 hours or carbon filter must be good. What 5 ppm / 30 min kills: E.coli, Salmonella, Cholera, Typhoid, Hepatitis A, Rota, Noro virus, Giardia - >99.99% kill. Cryptosporidium not killed - RO will block it. Safe? Yes upto 5 ppm safe for drinking. 4g in 1000L is safe for kids and cooking.