Originally Posted by tonedogz
Silicates are a contributor but not the sole contrbutor. Water quality such as ammonia, nitrites, nitrates and fish waste are also a factor as well as a low light conditions.
If you're referring to diatoms , silica is mandatory for their survival. The cell walls are made of silicon. No silicon, no cell walls, no diatoms. Diatoms can and do carbon fixation, but they cannot survive without silicon. Once they consume the silicon, diatoms will disappear.
If you do have nitrate issues, it CAN lend to the reproduction of diatoms as long as silicates are present. But even if you have perfectly clean nitrogenous free water but silicates are present, you will still have diatoms.
Therefore silicates are the 1 constant issue for diatoms.