Additives in the aquarium

[DEAD_BY_DAWN]

i was wondering should i be adding anything more than calcium to my tank , the waters great ph 8.1-8.2 cal 450ppm alk 12 dkh,no3 less than 2ppm corals all growing fast and the fish are healthy i do a 15% water change once per month and add 5mill if seachem's reef calcium once every 7 days and thats all ,other than i use Ro water for changes should i keep going this way or add any other Supplements like iodine etc