The square footage that one bag of Corral 2.68G will cover will vary depending on what you are treating. The manufacturer does not give settings for specific spreaders, but per the product label, "Calibrate to deliver 40 lbs. (1 bag) per 15,384 sq. ft. or 2.6 lbs./1,000 sq. ft. At the 1.7 lbs./1,000 sq. ft. rate, one bag covers 23,529 sq. ft."
Corral 2.68G is safe for established Bitterblue Grass when applied as labeled.