What tip weight are you using and how long are your arrows?

Even though the arrow says 65-80 does not really mean that in every case it will be suitable for a 65# to 80# bow.....especially shooting a 30" draw. I checked the CT web site and they don't specify what the actual spine is of that shaft (.340 maybe?)

What was the history of each of the arrows that broke? Did they ever take a glancing blow, smacked together while group shooting, etc...

While I don't shoot CT arrows, they are one of the major manufacturers of carbon shafts out there. I seriously doubt that their Whitetail shafts are problematic. Especially that you have broken two in the same place.

For the other manufacturers there are tons of great ones out there. You will hear from fans of all the other major brands, "XXXX brand is the best", "this arrow is super tough", yada yada yada. Truth be told, the quality of todays higher end carbon arrows is so high that I doubt that you could really tell the difference from one to the other.
Pick an arrow that matches your weight range and price range, and go from there.

I shoot Carbon Express Maxima 350s because I like thier weight forward design, but would have no problem switching to Gold Tips, Easton, Carbon Tech, or just about any other.