Patent ID: 7869963

Claim:
A system for calculating chemical usage comprising: a source of chemical feed; a supply tank of known capacity, which receives a chemical feed from the source of chemical feed, the tank mounted upon an electronic scale, the scale being capable of generating a series of signals related to the weight of the tank when empty and at various levels of fill; a water system which receives the chemical feed from the supply tank; and a system controller: for receiving a series of signals from the scale relating to the weight of the supply tank; for calculating chemical usage by inputting into the system controller the series of signal from the scale relating to the weight of the supply tank when empty and at various levels of fill; for refilling the supply tank from the source of chemical feed; for calculating a projected chemical usage during refilling of the supply tank by: obtaining a fill time for the refilling of the supply tank; and calculating the projected chemical usage during refilling based on a chemical feed rate times the fill time; and for calculating a total usage of chemical over a defined variable period of time by adding the projected chemical usage during refilling to chemical usage calculated by the system controller.