Old Bulbs = Algae

[chris88]

The spectrum and intensity does change in various lighting bulbs but its not the major causes of an algae bloom. Algae will grow because there is an access of nutrients. You could put a ton of red over a tank will low nutrients and no algae will grow. In fact that’s what people are doing with the new fiji purple and ati purple plus bulbs, they are adding red spectrum. If you have excess algae growth you will have access nutrients (nitrates, phosphates, silica, etc). However, the added red and yellow spectrum will make a high nutrient tank grow algae much faster because algae use red spectrum very well for photosynthesis.