Independent Store Brand Pond and Aquarium Clear Blocks will clear Green Water and Bacterial Algae in Approximately 7 Days and depending on water hardness will last 3 to 4 weeks.

The Majority of aquarium algae are actually bacteria, as a result this product is not herbicidal but anti-bacterial.

This block also assists in the prevention of Ammonia Spikes and will stabilize Aquarium PH by resisting with acidifying PH Reduction

This product comes in 4 Sizes -

RED 25gm - 1 Block treats 10-100 Litres
BLUE 25gm - 1 Block Treats 100-800 Litres
GREEN 25gm - 1 Block Treats 500-1500 Litres
LARGE GREEN 65gm - 1 Block Treats 100-3500 Litres