Tetra Nitrate Minus is used for the long-term reduction and control of nitrate leading to better water quality and less algae. – Harnesses natural process of biological denitrification- Simply add to aquarium once a week – no need for resins that have to be replaced or recharged- Maintains nitrate level below 30-40mg/l or less (in an average aquarium)- Helps control algae growth Produces no harmful by-products and is completely safe Add 2.5ml of Nitrate Minus per 10 litres of aquarium water on a weekly basis. Dose rate can be doubled for additional nitrate control. Depending on the starting concentration of nitrate in the aquarium it can take a few weeks to reach the desired level. Once achieved levels will remain low.