Shown here is an example of how our in line EC meter can be used to control the filling and fertilizer level in a holding tank for a recirculating and/or hydroponic system. The EC meter will open either the clear water (bypass) line and/or the feed line depending on the EC level in the holding tank, whenever the tank needs filling (float switch in tank). Note: Shown here with a Dosatron injector, but can use any source of fertilized water.