Sera Siporax Nitrate-Minus 500ml 145g

Sera Siporax Nitrate-Minus is a filtration media made from biopolymer that provides nourishment for denitrifying bacteria (i.e., bacteria that break down nitrogen) and thus helps to lower the nitrate levels in your aquarium. It is suitable for both freshwater and saltwater environments. 500 ml is sufficient for approximately a 40-gallon aquarium. The package contains 10 filtration balls, making dosing easy: 1 ball per 4 gallons of water. Due to their size, the balls are best suited for external filters.