I have 2 250MH bulbs mounted in the canopy on my 30" tank and I haven't had a problem with them. The two fans I have inside the canopy to cool the air works as well as when I was canopy-less and had the lights higher. As far as coral, the peak of my rocks are maybe halfway up the tank and the few lps and sps I have on top of the shelf is doing great and growing. The softies I have a quarter down the rocks and down to the sandbed are growing well too. Hope this helps.