I do add a decent load of Iodine to keep my xenia reproducing..
I think the bottom line is dont fix what isnt broken... but depending on what you are trying to do you may need to add a few things to produce a desired result..
I have an RO/DI unit and I change out about 10% every two weeks or so. I have (2) 48 gl cans that I store pre-mix in one and fresh in the other. I circulate and adjust the temp 24hrs prior to the salt change. For top off I just put in when needed. The next morning I run all the normal test and bump the calcium or Ph up if needed....
Seems to work fine for me as the Xenia are showing up all over. The other corals have steady growth and seem to be fine....