Patent ID: 8070941

Claim:
A system for cyclical control of a water characteristic without feedback comprising: a body of water; a circulation line to and from the body of water; a dispenser located in the circulation line; a dispensable material located in the dispenser; a pump for directing water into the circulation line; a solenoid valve located in the circulation line with said solenoid valve having an open condition to allow water to flow through the circulation line and a closed condition to prevent water from flowing through the circulation line; a bypass line for directing water from the pump back to the body of water when the solenoid valve is in a closed condition; and a time-based controller for on-the-go changing or maintaining the water characteristic, said controller repeatedly generating a dispensing cycle having a fixed time period P with a portion of the fixed time period P comprising a valve open signal to open the solenoid valve to allow water to flow through the dispenser and a remaining portion of the fixed time period P comprising a valve close signal to close the valve to prevent water from flowing through the dispenser to thereby periodically limit the dispensing of the dispensable material into the body of water, said controller maintaining the day-to-day control of the water characteristic by continually repeating the same dispensing cycle.