A tank inventory signaling apparatus that has gas cylinder tanks stored in an array at a tank farm. The gas cylinder tanks are placed where weight sensors detect whether a tank of the array is substantially full or not, say greater than 75% full. The substantially full tanks form the tank inventory at a tank farm that is transmitted to a networked local server. The information is relayed to a remote server having tank management software that orders replacement gas cylinders. A threshold level can be set in the inventory for order generation for all non-substantially full tanks in the array with the order generated at the remote server when the inventory drops below the threshold at a local server.