Just had a read of a blog by green aqua about different algae types. It says about a few types, BBA being my target algae. Cause, low ofr fluctuating co2, thrives in fast flow areas which it does in my tank. It goes on to say that co2 concentration should be at your desired level at lights on which we all know but also if any light including natural light at any point before artificial lighting photoperiod and gas on then this counts as low co2 or co2 should be in the tank. My tank has natural light before my lighting period, could this be a cause of my BBA of natural light adding to my photoperiod with low co2 before lights on and to much light overall throughout the day? I don't get much if any gsa though.