So here are my readings, all in one location:
Free Chlorine 6.4 ppm (two readings to confirm)
Combined Chlorine 0.4 ppm (two readings to confirm)
pH 7.4
Calcium Hardness 40ppm
CYA 40 ppm

Looking at the chlorine best guess chart, it appears my free chlorine level is too high.
How do I get rid of combined chlorine?