Here are some tips to decrease the growth of water plant:
1. Keep water changes at about 15 – 20% every other week.
2. Remove nitrates, as this is the primary food source for water plant.
3. Keep lights on 8-10 hours per day for planted aquariums.
4. Locate your new aquarium away from direct sunlight to discourage water plant growth in the water.
5. Green water plant typically occurs when there is too much light in an aquarium, keeping the aquarium away from an unshaded window.
6. Never use sunlight as your light source in an indoor tank. The sun can heat your aquarium and provide strong light, which boosts water plant growth.