Instant Ocean lacks the trace eliments and is not designed for reef tanks thats not to say it cant be used with good resaults if you dose the tank. Instant Ocean and reef crystals are made by the same company for to types of tanks fish only and reef tanks. With reef crystals if you do a 10% water change weekly dosing trace is not nessassary the salt mix takes care of it for you. As for tropic marin pro I have not used it myself but did look into it and everyone I talked to that used it told me they wernt impressed by it and switched back to REEF CRYSTALS. I dont recomend Instant Ocean for reef tanks expecialy for a nano reef! .....................................................................................................Go with IO, if a big place such as the GA aquarium uses it, then its got to be good. right?....................................................
................................................................................................... No A big tank is much different then a nano reef not to say it cant be done but for a few dollars more reef crystals is a much better mix and it is made for reef tanks. If cheap is what you are looking for then IO will work but for a few bucks more you get the peice of mind that your mix is giving you a good mix of trace elements.