The 24–7 Nutrient Monitor from Control Wizard Products is a great all around meter for nutrient applications needing constant monitoring. It measures PPM, pH and Temperature and with its large illuminated display it is easy to read from a distance. Calibration screws are conveniently located on the front for easy access. Control Wizard has priced the new 24-7 Nutrient Monitor to have the lowest MSRP of any constant read meter currently on the market. This low price will allow more first time growers to afford the quality and no hassle features of a constant read meter. Retail Price: $199.95