KH readings are not very important I don't have a test kit for them.
Young Stickle is the expert on this and I'll quote an extract from an article by him...
"Carbonate Hardness
Carbonate Hardness, also referred to as kH, is the result of contact between water (H2O) containing carbon dioxide (CO2) and lime or chalk (CaCO3). Carbon dioxide reduces calcium carbonate to calcium hydrogen carbonate, which imparts carbonate hardness to nearly all fresh waters. If the pH is acidic then the water will have a low kH value. When a high kH is maintained, the pH will stay stable and will then rarely fall. As the pH of the water becomes more acid, the kH decreases making the pH unstable, also stunting the growth of plants. kH can be easily increased using kH up and Carbonate Hardness Test Kit When breeding fish, carbonate hardness influences egg maturation, embryo hatching, and the wellbeing of the fry. As each species of fish are different and prefer different KH values, it is worth doing some research into each specific fish before trying to breed them. "
Hope that helps