Potassium calibration solution is needed to calibrate potassium ion meters for extra precision.
This potassium 150 ppm calibration solution will last up to 300 calibrations of LAQUAtwin K-11 meters. 
We recommend calibrating your LAQUAtwin meters daily (if you measure daily) or after every 10 measurements within a single day if you are testing more intensively.
 
⚫ Volume: 60 ml bottle with a twist top cap
⚫ Standard solution concentration: 150 ppm (150 mg/L) of Potassium (K+)
⚫ Compatible with HORIBA LAQUAtwin K-11 and B-731
⚫ Equivalent solution of HORIBA calibration solution Y031L
⚫ Made in USA