New Formula Kleen Pool. The product size is 10 x 1 Litre. 1 Litre now treats 6200 gallons! Kleenpool is a copper based long-life algicide which, when used in the correct proportions, can last for up to six months. Use summer and winter. If you are thinking of opening up your pool for the summer (De-winterising) then this is a great product. Shock dose your pool with Bio-Shock Xtra and when this is well mixed in add Kleenpool to keep your pool algae free for up to six months. Also ideal for using in the Spring when opening your pool up. Always read and adhere to the instructions on the pack and never directly mix chemicals. Don't forget, the price you see is the price you pay not a penny more. We sell chemicals cheap, not cheap chemicals!