any downstream module to an upstream module or in a direction opposite to arrows 17 18 in fig1 there is provided an extractor reuse tank 24 and a u201c pulse flow u201d tank 26 u201c pulse flow u201d tank 26 provides a supply of water to pumps 38 69 these pumps then transmit water at a high flow rate e g between 75 283 and 250 946 4 gallons liter per minute to a selected module or modules a plurality of conductivity sensors are provided as part of the apparatus 10 a in fig1 a conductivity sensor 27 is provided in the extractor reuse tank 24 another conductivity sensor 28 is provided in the pulse flow tank 26 a third conductivity sensor 29 is provided in the influent flow line 30 to monitor the conductivity of fresh water that is flowing through the influent flow line 30 from a selected source the source of fresh water in flow line 30 can include a cold source 79 of fresh water as well as a hot or tempered source 80 of fresh water the present invention monitors conductivity of water that is contained in the modules 1 10 and adjusts by adding fresh water or make up water in order to maintain the conductivity in modules 1 10 within a selected or desired range i e between about 100 micro siemens minimum value and a maximum value of about 1000 micro siemens above the conductivity value of the incoming or available water or source water because the fluid that is discharged from modules 9 and 10 through valves 63 and 64 enters extractor reuse tank 24 the conductivity sensor 27 in tank 24 monitors the conductivity of the tunnel.