The Bluelab pH Pen is the latest innovation for hand held pH meters and is the ultimate handy solution for measuring pH. Hydroponic growing lets you give the best care possible to your plants. The quality of care is in your control. The Bluelab pH Pen provides a compact, quick and handy way to manage the success of your crops to ensure maximum uptake of nutrients. Teamed with our Bluelab EC Pen or Bluelab ppm Pen, you have a handy, convenient and accurate system for ensuring optimum plant growth and health. The Bluelab pH Pen and conductivity pen range has been specially developed as an affordable and effective option for hobby or small scale growers.