Quote:
Originally Posted by shift

You multiply by 0.056; you are off by an order of magnitude.
To convert from German degrees to mg/L (ppm), multiply by 17.8. To go the other way, divide by 17.8 (or multiply by the inverse, which is 0.056).
Also, regarding your kH, I am unsure how you managed to measure 0.9 of a drop, so I would interpret your results with caution.