I just started cycling my tank about 3 days ago and i am just wondering how long I should wait before i start adding corals to my tank?

I would wait about 2 or 3 months after your tank has cycled to add them. This will give time for everything in your tank to settle down. Also, with the stock lighting for a biocube you will want to stick to soft corals, zoos, shrooms. Just do some research on the corals you want to add before had to see what kind of lighting and flow they like, and their diet. If you go to saltwaterfish.com you can check out info on a lot of different fish, corals, inverts....etc.

__________________
Chris

agreed. do wait for at least a month. then start with easy stuff like xenia. You can probably get some for cheap or free from another reefer. Add slow and make sure you know what they eat, what water movement they need, what nutriants they need, what are the dangers (toxins, stinging, etc), how to handle them and if they do sting, how do they do it and how far away other corals need to be... as well as your hand.

honestly...wait a week after cycle and put in a mushroom or two. see what happens.

__________________

You will need to wait on some coral before you try. Some require a stable tank with a lot of nutrients that must be upkept. Otherwise, a $100 coral will waste away. Go slow, really, doooo go slow. these things are expensive and some of them are taken from wild reefs, which means you have a responsibility to keep them alive because reefs, quite frankly, are dying. If many of them do die, at least we (as hobbyists) will have something to try to bring them back with.