Work out pool chlorine dose instantly with clear inputs, formula shown and shareable results.
One part per million in a cubic metre of water is one gram, so the chlorine needed is the ppm increase times the volume in cubic metres. Dividing by the product's available chlorine percentage gives the actual product weight — 65% dichlor needs about 1.5 times the calculated chlorine mass.
Chlorine dose
chlorine (g) = ppm increase x volume (m3); product = chlorine / available chlorine fraction
Because a cubic metre of water is 1,000 kg. One gram in 1,000,000 grams is one part per million exactly.
Raising free chlorine to 10 ppm or more to break down combined chloramines. It is done at dusk since sunlight destroys chlorine rapidly.