HI 981409 and HI 981410 TDS and EC meters have been specifically designed to address the needs of operators in hydroponics, greenhouses and nurseries. The meter employs the latest in custom-built application-specific microchips together with a purpose-built rugged housing to measure TDS and EC in fertilizer mixes. Calibration is easy and completely automatic. Simply press and hold the on/off button for a few seconds and the microchip inside the meter requests the appropriate calibration solution. Place the probe in the solution and wait until it is calibrated. No extra buttons to push or dials to turn!

HI 1220 probe measures 25 cm (10") and can even be used to mix the fertilizer solution! The custom-built microprocessor switches the meter off after five minutes of inactivity to save battery life. The outer casing also incorporates a molded eye so that the meter can be hung right where it is needed.