1. water + light = algae.
Solution:
1. If you don't have plants, minimize the amount of time overhead lights are on.
2. Use LED lighting
3. A little light goes a long way, don't mimic the sun unless you are keeping corals and or light loving plants.
4. Water change, water change, water change, repeat, repeat, repeat.
5. Cut back on feeding.
6. Employ snails or algae eating fish.
7. Introduce low light loving plants like java moss and java fern to out compete algae.
8. Cut back on feeding.
9. Move the lamp further away from the tank.
10. vacuum the substrate often.
11. Clean your filters often.