Some science behind the scenes
An algaecide or algicide is a substance used for killing and preventing the growth of algae. There are actually two types of algicide
- Natural algicides - Barley straw, for example can be placed in mesh bags and floated in fish ponds or water gardens to help reduce algal growth without harming pond plants and animals. “Barley straw has not been approved by the United States Environmental Protection Agency (EPA) for use as a pesticide and its effectiveness as an algaecide in ponds has produced mixed results during university testing in the United States”. It is used in the UK and Europe.
- Synthetic algicides - Synthetic algicides include copper sulphate and polyquat and it is this category in which we are interested in the context of toxins.
A full list of synthetic algicides is available on Alan Wood's Compendium of pesticide common names