The Guardian by Bluelab is a continous indicator for EC / ppm 700/TDS/CF/pH and temperature, which allow growers to optimize these parameters.
The Guardian runs on 220V and can be adapted to the wall or hung from a support. Probes are simply immersed in the solution. It also lets you manage your crops for 24 hours a day, and lets you set alarms for high and low setting. A screen with flashing light lets you know when a parameter is outside the normal range, allowing you to make adjustments quickly and efficiently.