A fire suppression system has a plurality of tank units (40, 42, 44, 46) each having: a tank body having a first port and an interior for storing at least one of fire suppressant and driver gas; a discharge assembly mounted to the first port and comprising: a discharge valve (50, 52); and a first monitoring switch or sensor (230; 240). A first monitoring unit (100) is coupled to the first monitoring switch or sensor of each said tank unit and configured to communicate with a remote monitoring location. For each of the tank units there is: a second monitoring switch or sensor (260, 280, 290); and a second monitoring unit (340) coupled to said second monitoring switch or sensor and configured to communicate with the remote monitoring location.