Planted Tank Guru
Join Date: Mar 2009
Location: Citrus County,Florida
If that green easily wipes off the glass with just a rub of your finger then it's GDA (green dust algae). My tanks have it pop up when I'm low on phosphate and high on nitrates. Suggest if it's not a huge PITA to clean the glass and do a large >50% WC right after. Change the bulb in the fixture. Some bulbs shift value faster than others, cheaper fill gas and the spectrum changes within a year while others seem to hold value for several years (save the old bulb in the tube supplied with the new one).
The Fraternity of Dirt
If at first you don't succeed,,, keep kicking it
2-75g planted, 5-55g planted, 5-20g planted, 110g w/30g sump, 8-10g,
2012 update adding table top pleco pans & a 90g (Nutz)