you use those to calibrate your pen I do mine every few months those packets are for 1 use after that get new ones or they sell bottles that you can pure some into a cup and calibrate those last a while.
u.g.u Reviewed by u.g.u on . Someone please explain... Can someone please explain the purpose of Ph buffers. Do you need them? Why are there specific amounts? Do they correlate with Ph up/down or IS ph up/down a buffer in its own? I bought a hanna 4 in one combo gro check. It came calibrated already but included Ph 4.01 and Ph 7.01 solutions for calibration? What are these packets? Do I need them? They are 20 mL each. Are these one time applications? Can I use them more than once? How do you store it if you can use it more than once because they Rating: 5