it is so easy, that we grow frogspawn and hammer cousins in one gallon vases for ten years and just keep fragging them forever, any large reef should have no trouble. frogs are 100% verifiably simple to keep in a pico reef, documented many times over. ** key details: pico reefs don't tinker with nutrients, nutrient chasing, pH concerns, we're not dosing stuff and removing stuff to the system which is the actual heart of upsetting things, if you don't strike the right balance.
the reason pico reefs always strike the right balance is their rules are simpler: change half or all the water weekly. all corals accept that, especially frogspawn, and that accomplishes all support required regardless of the salt mix you choose since the weekly work covers all param differences among salts, before the minimums are used up and the coral suffers. you simply feed it occasionally with any given reef food, Ill vote them as 100% simple corals depending on the system we choose to run. the tank they go in is the concern, not the actual coral they'll grow in a fishbowl with the barest of needs met.