well this is a somewhat debated topic. IMO, light doesnt CAUSE algae (like different light spectrums/intensity i mean)...it can just benefit the algae. There is generally some other cause for the algae, which would be nitrates, phosphates, tds, or something died in there and the nutrients from it were consumed too fast to show up on a test.
But first thing you gotta do is test for nitrates, phosphates, and total disolved solids (tds...and i guess they're called silicates as well...not sure tho) But imo, test at night. That will likely show you a different reading than what your'e getting now, because sometimes algae will release some of its nutrients (nitrates, etc..) at night when lights have been out for a while. Thats why sometimes it looks like its dieing at night. But then in the morning it takes those nutrients back up and will grow back.
But imo, your new light is just helping an already existing problem. Meaning there may not be enough nitrates or whatever to normally cause algae (tho technically any number of nitrates could fuel algae for some time), but that low number of nitrates with stronger lights might make a bigger impact...do you see what i mean?
