I've found with both my cars (Mitsu and Hyundai) there can be confusing specs for fluids (coolant, ATF, PS, etc.). I decided to just purchase them from the dealer's parts dept. It costs more than the stuff at AA or Autozone, but it's also stuff I only buy once every few years.
Try finding a coolant that is spec'd correctly for a Hyundai at an auto parts store. They probably would have to order it. I found it easier just to get the "Genuine Hyundai coolant" at the dealer for $20/gal., since it will last me 3 or 4 years anyway and the formulation is correct.