Review on Highly Accurate and Reliable 3-in-1 Professional Water Test Meter: TDS, EC, and Temperature. Complete with Protective Leather Case. by Andrew Kamkoff

I planted cherry tomatoes in my air garden - I had to turn on the lights when they grew 3 1/2 feet. I was concerned that they might not be getting enough food so I bought this device. First, EC is shown in microsiemens (US) and most hydroponics charts are shown in millisiemens (mS). You need to divide the readings by 1000 to compare them to the tables. In my garden it was 0594 ms or 0.594 ms. The charts call for 2.0 to 5.0 for tomatoes. Before I added any nutrients, I wanted to check the meter. The distilled water was 0008. I mixed 0.5 grams of table salt (iodized) with 500 ml of distilled water. In a lab with lab-grade components, this would be 2000 µs or 2.0 ms. The counter read $1,736, close enough to grow tomatoes given the wide variety. Now I can add nutrients without fear of burning the roots. Nice device for 15€.