I had a
MH light over my 12 gallon nano and heat was not an issue, but it was also an open top tank, and plumbed to a
sump. I know there are people who have used the
MH retrofit kits and were quite happy with them, but I believe most of them have had to use a drop-in chiller. Chillers for nanos aren't terribly expensive, and are fairly efficient to run, since many are based on a peltier device. If you really want to have an anemone/clown pair (which, I personaly think look GREAT in a nano), then these are options you'll have to investigate. You can get loads of good ideas and equipment at nanotuners.com and nanocustoms.com. They both have all KINDS of good stuff just for nanos.
There's no harm in leaving the carbon in there. I run carbon 24/7 on all of my tanks. I've not tried Purigen, but I too know a lot of reefers who swear by it as well. I've been thinking about picking up an extra phosban reactor to run some in. if I do, I'll surely post my opinion.
Oh, I forgot to ask. is there any cured
live rock in there with your base rock? Even if there's just a little bit, it will be greatly beneficial for seeding the base rock and the sandbed.
I'm not aware of the software you mention, but it seems like an Excel spreadsheet could be easily set up to do the same thing.
