Be sure to check for Phosphoric Acid. All the ready to drink teas I looked at contain this. It upsets the acid/base regulation of our bodies.
According to IP FAQ - "Acid / base balance plays a major role in physiology, particularly in such conditions as osteoporosis, gout, "hardening of the arteries" and a more acidic blood does not carry oxygen as well." They also mentioned bone spurs & kidney stones as possibilities.
Drinking it occassionaly would probably be OK but it probably wouldn't be good to drink it as a daily thing.