AN and GH 3-part are the same thing.

You will not be able to tell results from doing "1" tank. You can't do any better than 3-part. Will others work? Yes, but more people use 3 -part and therefore there is a much higher % of support. Good luck.
If you have enough, then grow 1 plant w/canna and see results. I think you will find...That the plants grow.