The chemical disinfectant feeder should be placed at a minimum of glasses. In these cases it is advisable to use an electric brush in combination with a detergent-sanitiser combination in the sink compartment used for washing dishes. Sink compartments must be large enough to accommodate the largest equipment or utensil to be cleaned, and each compartment must be supplied with adequate hot and cold running potable water. In the case of equipment that is too large to be sanitized by immersion, swabbing such equipment with a solution of at least double the required concentration must be approved for use with the specific make and model of the machine in question. A visual flow indicator can be used to help monitor the operation of the disinfectant supply. Other indicating devices such as audible alarms may also be used. Flow indicator devices must be installed so as to be easily visible to operators