If you decide to go with the 175w, then your main concern should be water
clarity (different than quality, eh?
). Carbon would not be an option...you'd need it, as well as regular maintenance needed to keep your water quality up as well. As long as your water clarity is very high, you shouldn't have a problem. I don't forsee SPS doing terribly well 3/4 of the way down the rock work though. I think you'd be limited to the upper 1/3 of the tank for SPS.