seems like it has both auto, and manual calibration

since its max is 1999ppm, you could try finding a calibration solution like 1500ppm, dip it in- set the pen to say 1500 (since you know the fluid is 1500)


Still wish i could find you the auto calibration fluid number...
Illusion Reviewed by Illusion on . TDS Meter Calibration Issues I'm hoping that there are some really smart folks out there that can help me understand something of the world of meter calibration. After making my purchase of an Oakton TDSTestr11, I asked the young genius behind the counter for an appropriate calibration solution, for which he hands me General Hydroponics Standard Calibration Solution. Here's where the confusion starts, as the package indicates that it calibrates to 1500ppm (NaCl), 2190ppm (442), and 2930S (microSiemens). So everything Rating: 5