hi Senna -
Good advice here.
As for what nutes to use, oh dear, that's a hot topic on any forum. I don't have any experience with Canna, but it might be good for you to post a new thread with your question.
WArning - you're going to get a whole bunch of responses that are going to conflict. Look for people who can offer growing experience, not just those who have crap to say about companies.
Personally, I use Advanced Nutrients, and it works well for me. But check out all the brands so you can make the best decisoin for your growing needs.