Diestro Services now offer HM Digital handheld and portable TDS, EC, pH and ORP testers, in-line monitors, controllers and accessories for reverse osmosis (RO) water filters, water purification systems, hydroponics, aquariums, pools and many other applications are superior in construction and performance, yet made available at a very economic cost. HM Digital, Inc. is the … Continue reading HM Digital TDS, pH Radox Hand Held Test Instruments