The Milwaukee MC740 PRO Conductivity (EC) controller and pump lets you measure and adjust EC levels automatically.

Control the EC and Fertilizer Dosage in your Tank Automatically
Control the EC and Fertilizer Dosage in your Tank Automatically. The MC740 kit includes the MC311 EC controller and the MP810 dosing pump to automatically monitor and fine-tune EC levels. Just set your EC parameters and let the Milwaukee EC Controller and pump do the rest. Common uses are nutrient tanks.