Kolor Kut Water Finding Paste is used to test fuel in storage tanks for water contamination. The paste changes colour when water is present, therefore showing contamination within the fuel. Simply apply the paste to a long item and dip into your storage tank (reaching the very bottom) and remove again. Once removed it will be evident whether there is water present or not. Kolor Kut Water Finding Paste will successfully gauge the presence of water in petrol, diesel, sulphuric acid, nitric acid, hydrochloric acid, and ammonia.