I used that light for about a month on my 10 and it left shrooms reaching for light. While 2 would help I imagine, it would be way cheaper to get a par38 bulb (I'm using reefkoi's version and love it and it's only $80). If you want pictures of the corals under the par bulb you can check my thread "operation clown goby rescue" a little further down the page. Just my $.02 though