Tank Blox can be used in small dams and large water containers to prevent algal growth. One block will treat about 70,000 litres (15,000 gal) of water. If less water is to be treated, break the block proportionately. Each block contains 63gm/kg of copper, present as copper sulphate. The block should take 2-4 weeks to dissolve. Replace when nearly all dissolved. Dams and tanks should still be cleaned regularly to ensure a clean water supply.
Note: Tank Blox are not recommended for human consumption.
