I made my second batch of pecan turtles recently and thought I had corrected the "rock hard" caramel encountered with the first try. They were delicious initially but, after sitting for a few days, the caramel turned sugary. Can the food docs out there tell me what went wrong? Also, can you recommend a good candy thermometer? I have purchased two so far and found both to be very poorly designed and almost impossible to read while caramel is steaming in the pan. Thanks!