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