What does the GH read?
My apologies as this is probably a stupid question... does the water turn yellow immediately after putting in one drop from the KH bottle and mixed up?
If this is for the N. davidi (cherry shrimp), most places actually recommend at least a TDS of 150 for them. Some might say a TDS of 80+ is fine, but I've had better luck with higher TDS. Around 80, the water was too soft and the shrimp died from molting problems.