I have a bunch of corals and I test for the following: ammonia, trites, trates, hi ph, phosphates, alkalinity, magnesium & calcium. When I was doing my weekly water changes I didn't have any drops any parameters, BUT I have recently switched my 125g to every two or three weeks for water changes. I also have about 30 corals in the tank, some large ones. In my opinion, most likely you will not have to dose anything if you keep up with the water changes.
125g Reef - 60g Rimless FOWLR-125g Malawi Cichlids- 29G Biocube REEF-90G Fowlr-8g Reef
I have a mix of many different saltwater fish amongst my tanks, too many to actually list here. LOL