To control algae, add one piece per 20L or one complete block per 120L of water.
This block is best used as a preventative or when algae first appears or after cleaning an algae infested aquarium
Blocks will dissolve over 7-14 days depending on water conditions and circulation
If possible control the amount of sunlight or artificial light to reduce the growth of algae
Repeat only when algae reappears
To prevent oxygen depletion, remove heavy algae growths mechanically before treatment and aerate the water after use