цифров PH метър ph метър PH тестер SmartSensor AS218 0.0014.00pH Инструмент за измерване на влага вода PH киселинномер

 the preparation of the buffer solution1. PH4 buffer solution with accessories distribution of  powder in 250 ml distilled water, fully dissolved  dilution 30 minutes.2. PH6.86 buffer solution with accessories distribution  of powder in 250 ml distilled water, fully dissolved  dilution 30 minutes.3. PH9.18 buffer solution with accessories distribution  of powder in 250 ml distilled water, fully dissolved  dilution 30 minutes.