These are tools I use for hydroponics. There are better and worse out there.
Bluelab pH pen – This is a necessary tool to test the pH of your hydroponic solution. I have used the cheap ~10.00 meters and they are garbage. This one has worked really well, and gives fast accurate readings. It will need to be stored and calibrated properly, so you’ll need storage and calibration solutions. You will also need pH up and down solutions to adjust the pH to your desired target level.
pH probe KCl Storage Solution – A few drops of this go inside the cap where the probe touches. This keeps the probe properly hydrated. If you let it dry out, it could damage the pH meter.
The following calibration solutions are required to properly calibrate your pH tester.
pH 7.0 Calibration Solution
Conductivity meters are used to test the strength of your nutrient solution. It’s important to know the strength of your hydroponic nutrients. It they are too week, the plants will be undernourished. If it’s too strong, the plants can be (nutrient) burned or even killed.
Bluelab Commercial Truncheon – This the meter I use. I like it because it’s easy to use, waterproof and doesn’t require calibration. It shows EC, CF, ppm 700 and ppm 500 scales. If has an accuracy range of .1 EC or 50 ppm, which is sufficient for most applications. If you more than that, choose a different type of meter such as the Bluelab ppm pen.
Bluelab ppm pen
An accurate (to .10/gram) scale is necessary for measuring dry nutrients if you mix your own, such as with MasterBlend, Magnesium Sulfate and Calcium Nitrate. I use the American Weigh, AWS-600 scale, with the 500 gram calibration weight. This scale is very accurate and inexpensive, and has a 10 year warranty.
AWS-600-BLK Precision scales
500 Gram Calibration Weight Calibration weight