So this is your 29? What exactly do you have for lighting? How much flow? How manly lbs of LR do you have?
The short answer is not much. If you have a decent amount of LR, decent flow, and decent lighting, you should be OK to keep softies and probably most LPS. Also, what salt mix do you use?
I kept an open brain under pc lighting for 8 months before upgrading with good results, but I fed it every 3-5 days. Don't worry about Ca if you don't plan on keeping SPS, your weekly w/c's will replenish this and just about everything else you need. I suggest you think a bit about salt as well. I like Seachem reef salt becaiuse it has higher levels of both Ca and Mg, as well as having an awesome buffering capacity. I like this salt because I don't have to add Ca or Mg to keep levels up, and it also keeps my alkalinity up. Don't go crazy with dosing, either. Add as little as possible.
ONLY USE RODI WATER for your waterchanges. This will keep phosphate and other junk out of your water. Test your water parameters religiously ntil you know how your tank behaves. You should test for pH, kH, NO2, NO3, and NH at least. Test before w/c's and keep a log. If you start adding sps, you will also want to check Ca and Mg. Corals like stable parameters, and if you do your weekly w/c's on a regular schedule, you will not need to worry about skimming and will have happy corals.