A method of maintaining a floor comprises discharging a diluting fluid from a first reservoir to a mixing apparatus, discharging a cleaner concentrate from a second reservoir to the mixing apparatus, continuously identifying changes in fluid level within the first reservoir with a level sensor, providing a first signal indicative of an identified change in fluid level, passing the cleaner concentrate and diluting fluid through a flow control device, and processing the first signal to generate an output signal and controlling operation of the pump and the flow control device in response to the output signal to provide a flow of fluid to a cleaning device at a substantially constant ratio of the diluting fluid from the first reservoir to the cleaner concentrate from the second reservoir for substantially all fluid levels of the first reservoir.