I have heard old bulbs will promote bad algae, my T-5's are about a year old and I have been battling green algae on my rock and sand bed could it be the bulbs? all params are fine I have a 100 gallon SPS and LPS dominate tank every thing is growing well. all bulbs are overdriven and are going to be replaced when new ones come in. I do 15 gal water changes every 2 weeks with ro/di TDS 1 and no phosphates and I dont over feed my 7 fish. I'd like to hear if anyone has had algae outbreaks cause of their bulbs?