Bark chippings only sounds wrong.
I use a very sandy/gritty potting mix because they last longer than more peat based blends. Cacti or succulent mix would be good, you'd just need to add a slow-release fertiliser.

Organic matter does break down quickly and is likely to leave a heavier soggy medium. You'd probably need to repot more frequently if you used bark (or other wholly organic medium). You'd be better off sticking with your sand.