I dose ammonium chloride on a daily basis. As for Vit B complexes, I dosed a small (maybe not that small after all) amount into the tank, and was rewarded with explosive dino growth. So got to be more careful with that.I believe that many reef tanks could benefit from ammonia dosing, there is nothing wrong with it if it is done correctly(I believe it is better than nitrate dosing). If you dose ammonium you need keep in mind that when ammonia is added by fish, it is accompanied by some B vitamins(I believe), and trace elements and organic carbon from fish food, and because of this, I believe that dosing ammonium is more likely to create imbalances than ammonia added by fish, except for a high phosphate imbalance. If you dose ammonium, it is more likely that you will need to dose trace elements, and B vitamins(dosing B vitamins is easy, and is cheap long-term.
I believe that B vitamins are needed for heterotrophic bacteria in a reef tank. I believe that heterotrophic bacteria can compete with cyano, I believe that the bacteria can be used as food for at least many types of corals, and I think that they are capable of consuming all of the DOC that comes from algae.
If an algae filter is big enough I believe that ammonium dosing can be used to control the phosphate level.