Hmm..oic..I'm not familiar with the usage of ppm for kH. So far the test kits I have used only use the units milliequivalents per liter(mEq/l) or in dKH. Anyway...if you could ask someone with more reliable test kits (Salifert, mini labour, etc)to test the results of your test kit with theirs it would be best so that you can be sure you are getting the right readings.