I have 3 2 ft. lights running from front to back over each 1/3 of the tank (6') Each light has 4 t-5 ho's and a 250 watt MH. I started turning on the t5s for an hour a day and bumped it up an hour a day until it was about 7 hours. Then I started the halides an hour a day and it seemed the algae went crazy when they were on for about 5 hrs. Two days later only the big rock has hair algae the smaller ones just some diatoms which is normal. Could it be something in the big rock ?