Bluelab Growers ToolboxA handy pack with everything you need to get going and keep growing! The Bluelab Growers Toolbox combines the essential tools you need to easily manage your crop by measuring the pH, conductivity (ppm) and temperature of the nutrient solution. Learn the hydroponics basics with the Grow Book, so you can get going And keep growing with the ultimate handy team, the Bluelab pH Pen and Bluelab ppm Pen. These clever little pens make it easy to measure the