Voted number 1 in a user survey, Cloverleaf Blanket Answer is a unique blend of minerals and enzymes to combat blanket weed. Blanket weed can quickly spread over the pond and stop light and oxygen from other pond life, so not only does it look unsightly, it also damages the delicate eco-balance of your pond. Blanket Answer is safe to use with all pond fish, plants and even with biological filtration systems. It can be used repeatedly to shift a stubborn problem, especially over the summer months. A 800g bottle will treat ponds up to 10,000 litres (40 ml treats 500 litres) (200g treats 2,500 litres), so a little goes a long way. It\'s a good product to keep to hand all year round in case the problem occurs.