So, I received 2 new bottles of reagent and the replacement PVC tubing from Marco. I changed out the PVC tubing with no affect. As for the bottle of reagent, it is close to empty so I'll just run it out. Not going to waste the money. My range is still a steady 10.7 to 10.9 so I went ahead and adjusted the viewed number by -24%. I now measure right on with my Hanna checker, Red Sea and Salifert. I check them frequently. I guess if this is how it has to be, I can live with it. I am curious tho to see what happens when I change to a fresh bottle of reagent.