I have never had this problem before, but it is starting to drive me nuts. The tank has just finished the cycle and I had no algae on the glass even while I was running the lights for a few hours a day. Now I run the lights on the regular cycle and the algae grows like crazy. I can use the magnets and clean the glass and two hours later the glass is covered again and looks like I didn't touch it. My lights are 4 T5's and 2x150 MH. This is a 4 foot fixture so the T5's are 54watts each. Why is there so much algae growth so quickly.