Supa Anti-Algae Pond Block.  When placed into the pond this block slowly dissolves releasing di-methyl urea into the pond waters. Whilst totally harmless to fish and healthy pond plants this inhibits the growth of water born algae. Prevention is always better than cure so the introduction of this item in early Spring will prevent build up of algae as the weather warms.

Supa Pond Block also helps to neutralise build up of acidity in pond waters.

Use one block per 1,000 litres of water.  Replace when fully dissolved.