I just went through this a few days ago myself and found a really simple solution. I just purchased a power compact and a few months of having it the green slime algae took over my rocks and sand and glass. I do have corals so was wondering about the light thing too. Now rught now I am still using my well water for the salt changes. I took and put on a small powered flourescent fixture and bulb about a 36" on my 125 gal right in the middle and I turn it on from 8am to 11am and then the power compact and literally within two days the green was all gone!! Including the glass and sand!! The smaller ligfht allows the good bacteria a chance to feed and take care of all of that !!! Hope this helps, my tank is back to sparkling clean!!
