I have cloudy water all of the sudden and need to know the differerence between green dust and green water. Is green dust algea a floating dust or is it just on surfaces? I need to figure it out before I try to find a solution.
Phosphate isn't the cause of algae. Too much light for the maintenance you do can be a problem, and not enough healthy growing plants can be a major problem, since we depend on the plants to prevent algae spores from ever noticing any ammonia in the tank. I'm guessing if you have green water, it followed an upheaval of the substrate, which can release lots of ammonia and other organic gook into the water. If you don't do a big water change immediately after such an upheaval you do risk an algae outbreak. Also, if you have a lot of light and don't have a stable supply of CO2 in the water, that can start an algae outbreak too.