Grayish Red Growth

[freedom75]

Guys I need help. I have a alge that is growing in my tank. It is grayish red and very thick. Air bubbles coomes up out of it and it gets bad enough that the air bubbles will float it to the top somtimes in patches. I just added a new set of lights it has 2 175Watt MH and 4 55 Watt PC actinic bulbs alot of light I thought thought that this would help but only adding additional Heat. I need advice. Some of my stuff can be seen at http://home.triad.rr.com/jwray/reef.html Altough this does not show the problem... This tank is 3.5 months old water balance is good no nirate,nitrites,ammonia. PH is 8.1 any help would be great... Thank You