HS aqua Nitrate Minus is an ion exchanger based filter material. It exchanges the nitrate for the less harmful chloride. This inhibits and prevents algae growth.

500 ml is sufficient for 500-1000 l aquarium water depending on the initial concentration of nitrate.
1000 ml is sufficient for 1000-2000 l aquarium water depending on the initial concentration of nitrate.
Replace the material after 3 months or after an increase in the nitrate level.