Correct. You need solutions at those levels. As sovreign said, they're typically available at levels around 4, 7, and 10.

With the example code, you'd insert into the buffer solution, then run (for example, in Python) ``` # place in buffer of nominal ph of 10 V1, T1 = sensor.calibrate(CalSlot.ONE, 10, OnBoard()) # place in buffer of nominal ph of 7 V2, T2 = sensor.calibrate(CalSlot.TWO, 7, OnBoard())

Then save V1, T1, and the buffers you used to a file, your database etc. Or just write them to your `py file.` The MyCodo version, for example, handles that automatically.

Then next time you run, load sensor.calibrate_all( CalPt(0.,7., 23), CalPt(-0.17, 10., 23) ) If you just edited the file. Or those values would be loaded from a db.

Typically with ph sensors like this you also get three ph packets(4.01, 6.86, 9.18) which when mixed with distilled water get you a baseline ph for calibration.