Testing Parameters For Coral

I'm new to reef keeping and I just added over the last couple of weeks some basic coral to get me started (Mushrooms, Xenia, Zoas, and a Green Star Polyp. I've read that for the most part these are hardt corals and good for beginners. I would like to start testing my water parameters for coral keeping as right now I have only been testing my water for amonia, ph, nitrates and nitrites. What kits to you recommend and what exactly do I need to adjust levels if I need to? I've read about people using iodine but I'm not sure what for.