Hi RedEyeReef,
In repply to your question, as with all MH set ups, if it is needed, I can buy a chiller. In the case of my nano, an ice probe. However, if I remove my heater from the equation, I suspect since I keep my apartment at a comfortable 68 - 70 degrees (I like it cold), that the MH should do the job quite nicely. The MH I am ordering is 175 watts, and should be sufficient for the 1 or 2 SPS I want, as they'll be near the top, and maybe a crocea clam. These will be bought later however, as my tank is currently only nearing the 3 month old mark. I also intend to add a Rubbermaid stock tank of 70 - 100 gallons for a sump/refugium. This should solve volume, heat and stability issues. I'll be doing the MH/heater (or lack of heater) tempeture test before I add any corals on a day off, and will keep a sharp eye on the tank, to make sure "Merlot" my baby maroon clown isn't stressed. I thank you for your concern though, and if you have any improvement suggestions to my current plans, you're welcome to post em.