I'm running two 250 MH on the corner with lumen bright reflectors. Covers every square inch. It may be a little over kill but the corals are happy. I might cut back to one. And use some LED strip lighting to get the darker areas. I eventually am going to make the full plunge to LEDs but not until after my move in june. Not really doing a lot of upgrades to the tanks until after then. I can imagine that half circle is a tricky one to light. It looked awesome the last time i saw it. A headache non the less.