I feed them once for awhile whenever fed my fish with mysis. I rotated the food between dyi, pellets, flake, rod's food, Jane's food,Larry's food...etc.
I used baking soda for alk and pure ice smelt from BJs for cal chloride. It is said:"100% pure calcium chloride". so far, I do not have any problem with my SPS corals.
dose or not is also depending on what corals you have in your tank. as bigger tank is more stable than smaller tank. Also considering sps vs lps vs soft corals. some salt branch claimed to have high level of cal, alk, mag and others but its price is much higher. so you have to put that into account too. Whichever works best for you in the long run than do it.