So, you use Kushie Kush like this:
Use 2 mL per Liter during weeks 1 through 6 of your flowering phase.
The Bud Candy should be used:
Use 2 mL per Liter during weeks 1 through 6 of your flowering phase.
So, yes, you can use them at the same time. Though I would suggest using less than the instructions say to use. Kushie Kush is some super powerful stuff and a little goes a long way, from what I've seen in other grows.
Personally, I think the entire AN lineup is worth buying and using all at the same time, but I just get confused with all of the products sometimes, so I try to use as few as possible. You know, KISS, Keep It Simple Stupid, formula.
Some base nutes, a few dazzling additives and some Overdrive or Final Phase too.