How can I stop double calendar notifications?

[AC Question]

Double calendar notifications

I just got the Galaxy S6 and have started getting double notifications for calendar entries. I'm using Business Calendar 2 as my main calendar synced with google. I found that I needed to have google calendar installed for this to work, is that true?
It looks like there is also a Samsung Calendar that I can't seem to get rid of, bloatware I guess. I didn't have this problem with the S4.
Does anyone know if there is a solution to this issue.

Thanks