Suppression tank scale and level determination

A fire suppression system comprising:

• a tank (22;
• 410) having a first port (40;
• 420) and an interior (32);
• at least one of a fire suppressant and a fire suppression propellant in the interior;
• a discharge assembly (46;
• 422) mounted to the first port and comprising a discharge valve (48;
• 424);
• a base (102);
• one or more springs (112) positioned to support the tank atop the base along a range of motion between a first condition and a second condition, the first condition relaxed relative to the second condition and the second condition compressed relative to the first condition;
• a first magnetic member (142) mounted to the base;
• a second magnetic member (140) mounted relative to the tank so that a spacing between the first magnetic member and the second magnetic member decreases as the tank moves when the one or more springs go from the first condition to the second condition, at least one of the first magnetic member and the second magnetic member being a permanent magnet;
• and
• a magnetic field sensor (160) positioned to detect changes in a magnetic field associated with changes in said spacing.