Color charts on the tubes match up pretty well. Started doing parallel tests, and only once did they come close to matching. The sampling with the k1000 consistently produces a more reddish orange color than the k2006 in my sampling over the last few weeks. Dye looks good - still red and kit is less than 8 months old. While I understand I need to be matching hue, not sure I understand using fewer drops, as I have not had a problem in matching sample color with comparator tube. I did attempt a couple of times adding more drops and it did intensify the hue, but only moved the the "visible match" up one on the scale. To me it made it a bit harder to match the sample to the tube colors. I have not reacted to the low ph yet, but ready to do so if it gets worse. Thanks