I have a number of customers who swear by daily iodine additions. I tried it on my tank and things looked great for about a week and then I had a big hair algae bloom so I quit using it. If you do use it get the Salifert iodine test kit, it's the only decent one that I know of.

As far as Ca goes I would recommend you use balanced supplement such as kalkwasser, two part additive (Tech CB, B-Ionic, C-Balance etc.). Alot of customers seem to like Kents Liquid Reactor as well but it clouds your water for a couple of hours after you use it. The upside to Liquid Reactor is that it takes care of Ca and Alk. I would stay away from calcium chloride (i.e. liquid calcium, turbo calcium) unless you plan on doing frequent water changes.

I just use Seachem's marine buffer for ph/alk but you shouldn't have to use it to much if you stick with a balanced Ca supplement. I've used about half a jar in the past year on my 140 gallon tank.