Have you checked for mold? Look in the soil for any signs of mold. The gnats themselves usually don't cause too much problems, but instead are signs of other problems...most commonly mold.
Also, with CFL's fewer bigger lights is better than lots of small ones in terms of heat generated...you have to find a good balance between light distribution and heat production, ive noticed the 40 watters i have make pretty much the same amount of heat as the 65 watter I have, I usually keep a mix of 23/40/65 watters and try to find a good balance between temperature and light distribution.
Also, with CFL's fewer bigger lights is better than lots of small ones in terms of heat generated...you have to find a good balance between light distribution and heat production, ive noticed the 40 watters i have make pretty much the same amount of heat as the 65 watter I have, I usually keep a mix of 23/40/65 watters and try to find a good balance between temperature and light distribution.