The purpose of the dosing system is to pump a predetermined volume of septic tank effluent from the dosing tank to the mound. The pump must be turned on when enough septic tank effluent collects in the tank, and shut off when the effluent remaining keeps the pump submerged. The pump is usually controlled by float switches suspended in the tank, as shown in Figure 16. A third switch is used to trigger an alarm when the effluent collected in the dosing tank reaches twice the dose amount (emergency level). The settings for the switches are determined based on the dosing volume and the size and geometry of the tank. The procedure for setting the levels for the controls is presented in step 17, along with an example.