I'm a fan of the Canna. And yeah, if you are relatively new to playing with nutes and supplements, a lineup/nute system designed to work together, and with feeding schedules available, is nice. I'm actually about to set up a grow for a buddy in promix with the AN lineup, complete- the nutes cost $400 to start but are supposed to be FOR a soilless medium, specifically promix, and just mix and use.
I think the clusterfuck is a good description for the source of your problems. Something is locking out the calcium in your water. It SHOULD be available but isn't, and your pH sounds like it's correct! AAARGH!