Just thought I would share my experience. Recently cut my lighting and ferts in half since my tank was fully carpeted with HC and was trying to slow its growth. Almost immediately brown algae started forming on the leaves and fixtures, not everywhere, not an all out bloom, but noticeable. On the next water change went back to normal fert dosage, trimmed a bit, and went back to full lighting and...algae is disappearing, almost completely gone. I suppose this might sound like "duh" to some out there, but there also seem to be just as many that are confused about algae as I can be. This worked for me, and backs up what I've read and heard about diatoms taking advantage of inadequate lighting and also giving your plants the tools they need to out compete algae. Hope this can help someone!