hello all Can someone tell me how to use this? please emphasize the description of not have any liquids into calibrate seems to me to like new buys in but is making a calibrated measurement of pure water is shown is
pH-8,3 and tds-ppm-0,79
http://cgi.ebay.pl/SET-TDS-Meter-PH...K_Swimming_Pools_Hot_Tubs?hash=item4a9c34595b


http://cgi.ebay.pl/SET-TDS-Meter-PH...K_Swimming_Pools_Hot_Tubs?hash=item4a9c34595b