I thought that what I was experiencing with my pH tests had to do with older reagents - but I replaced them Friday and I have the same issue:

When I test my pH with my trusty K2006 kit, the color endpoint is not a blue-red cast - its more of a yellow-red - BUT it is not in the acid range as far as I can tell. I have been guesstimating my water to be pretty solid at around 7.5 because the intensity of the color fits between 7.4 and 7.6. I get the same color point with the old and new reagents and with 2 separate comparator blocks I have.

When I test with my daily rainbow, I am getting a definite blue-red color set and it appears to be in the basic range - as if I need acid added.

When I tested my rainwater - which has been a lot lately - it is below 6.8 in all three tests. My alkalinity is steady between 70-80 since I opened in May.

I don't know what sets of numbers to go with.

I have a 24K IG vinyl 18x42 with a Hayward 1hp SuperPump and Hayward EC-65 DE filter.