According to {TAIL ~ a feature} of {HEAD ~ the invention}, the tank has a number of water outlets spaced along the lower water collection region and controlled by valves which may be programmed to open periodically and sequentially 
According to { TAIL ~ a feature } of { HEAD ~ the invention } , the tank has a number of water outlets spaced along the lower water collection region and controlled by valves which may be programmed to open periodically and sequentially
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