This Standard validates the calibration of the HI 713 Phosphate Checker HC Colorimeter.
(2)Standards (1) 0.00 and (1) 1.00 ppm phosphate
Liquid Reagents for Alkalinity Checker HC Liquid Reagents for 25 Alkalinity Tests
The live help is excellent by the way. Will re-use your shop again as I found you to be very helpful.