For tracing the direction of flow or to where a drain pipe runs. The recommended dilution rate is approx. 230g to 9 litres of water. The liquid is then use at a rate of 140ml-250ml per 450 litres, depending on the ground conditions. Approx. 230g of drain dye will treat 28, 800 litres at 140ml per 450 litres & up to 16, 200 litres at 250ml per 450 litres.