The grapefruit I have growing is a 6 yr old Croxton pink... named after Dr Croxton from Columbia SC who grew it from seedlings.. I suspect it to be a Thompson pink Gpft. They seem to tolerate considerable cold and people seem to love the flavor! They ripen in the Oct/Nov time frame which is perfect for me. This year, the tree probably had 200 + fruit. Our local store was selling pink gpft for 1.59 each in Oct. Do the math, not a bad investment for one tree!
BTW, I got the budstick from Dr Croxton for the tree I have growing on a cold Jan. morning.. It was 14F that morning if I recall correctly!