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 1000-3500 Litres
