How should I add chlorine to a pool safely?

Always pour liquid chlorine into a bucket of water, never the other way around — reversing that order creates a chemical reaction that can splash boiling-hot bleach into your face. Pre-dilute in a clean five-gallon bucket, pour near the return jet, and wear gloves and eye protection. Add chlorine at dusk to avoid UV loss, and store the jug upright in a cool, shaded place away from acid or stabilizer.