Calculate a rectangular pool's water volume and the chlorine dose needed to reach a target free-chlorine level.
Chlorine dose uses the standard formula: grams = (target ppm × volume in liters) ÷ (10 × % available chlorine). Test actual free-chlorine level with a test kit before and after dosing — this assumes starting from zero residual chlorine.
Most residential pools slope from a shallower end to a deeper end. Using the average of the shallow and deep depths gives an accurate volume for a simple sloped-bottom rectangular pool — irregular or free-form shapes need a more detailed calculation.
grams needed = (target ppm × volume in liters) ÷ (10 × % available chlorine) is the standard pool-chemistry formula — it accounts for the fact that a product like calcium hypochlorite is only 65% actual chlorine by weight, so you need proportionally more of the product to deliver the same dose as a purer source.
1–3 ppm free chlorine is the standard target range for a safely sanitized residential pool. Test with a kit regularly — chlorine demand changes with bather load, sunlight (UV breaks down chlorine) and organic contamination, so this is a starting dose, not a fixed daily schedule.