I just recently bought a Trident and on Friday for the first time replaced Reagent A. I was planning to do the calibration this morning but when I looked inside the box of reagents, there's only one calbration solution included. If I use it, I won't have any solution left for when I switch out Reagents A, B & C in another month. My question is this...should I do the calibration now just on Reagent A or wait until I switch out all three?