Need some help.

PLX 3EX user. I want to learn how to program the following situation. During manual water change the low water sensor (level 3 sensor set as leakage) eventually goes into alarm because i intentionally change more water than de safe level. On socket S2 and 4 are resp. a heater and streampumps that will run dry or get damaged. How do i program:

if level sensor = in alarm, trigger S2+S4 to switch off and vise versa, Sockets S2+S4 switch on automatically once the level sensor indicates that water level is back in safe mode (high water), because water has past the sensor., so i need some specific do this and do that insruction in PLC.

Many thanks.