DM-1 from HM Digital is a continuous TDS meter.

DM-1 allows measurement of water entering and leaving reverse osmosis systems and all systems that require continuous water quality monitoring.

TDS stands for Total Dissolved Solids that is the amount of all ions present in a volume of water including heavy metals (copper, lead, etc.) and is expressed in mg/L or ppm (parts per million).

The TDS value is related to water quality and the functionality of the reverse osmosis membrane. The higher the TDS value, the lower the water quality. A drinking water quality should not >500 mg/l.

Using the DM-1 on aquarium reverse osmosis systems allows the quality of produced water and efficiency of filters to be assessed, allowing the time for replacement to be evaluated.

DM-1 is calibrated at the factory. Calibration can be done with the 342 ppm NaCl solution, but it is not usually necessary.

Features:

• Displays the TDS of 'water with two electrodes placed in two convenient 1/4” quick couplings.
• Accurate since microprocessor-controlled
• Auto power off. Unit turns off after 10 minutes of non-use
• Automatic dual readings.
• 0 to 999 ppm with a resolution of 1 ppm
• 1000 to 9990 with a resolution of 10 ppm.
• The instrument is calibrated. Can be calibrated with a mini screwdriver and 342 mg/L NaCl solution.
• Quick and fast installation.

Specifications:

• Measurement range : 0 - 9990 ppm
• Accuracy : +/- 2%
• Standard 1/4” fittings
• Battery life: more than 1000 hours of continuous use
• Dimensions: 7.6 x 2 x 4.7
• Weight: 79.4 g.