Green Water Control 250ml

King British Green Water Control targets the tiny unicellular algae in your pond that cause “green water”. This special additive causes the algae to clump together and fall to the bottom of the pond, where they can be sieved out or where the light levels are too low for them to thrive. “Green Water” is unsightly, can clog filters, and can be bad for fish health, as it can reduce oxygen availability at night. One 250 ml bottle will treat 2,250 litres of pond water.