Bluelab pH PenThe Bluelab pH Pen is the most simple, user friendly pH and temperature testing tool on the market. Testing your nutrient solution has never been this fast or easy. Simply turn the pen on, stick it in your solution, and read the pH temp. For just over $100, you won't find a pH device this accurate, reliable, and simple! Benfits Of Testing With The Bluelab pH Pen If you have grown before, you understand how fickle plants can be sometimes. They'll only