Umm that I am not sure... I know the above will test for KH/GH and then there is this thing:
HM Digital TDS-3 Handheld TDS Meter With Carrying Case, 0 - 9990 ppm TDS Measurement Range, 1 ppm Resolution, +/- 2% Readout Accuracy - Amazon.com
which will test for TDS. I was never sure what to do...