Apparatus to implement automatic refilling functionality for a liquid holding tank that is the final tank in a flow-path-interconnected series of tanks

A tank refilling system configured to keep a height of liquid level in a destination tank close to a predetermined fill line;

• said tank refilling system comprising:
• a) a source tank comprising a source tank liquid entrance opening;
• b) said destination tank comprising a destination tank liquid entrance opening and, a destination tank liquid discharge valve;
• c) a secondary process comprising a secondary process liquid inlet and, a secondary process liquid discharge outlet;
• said secondary process liquid inlet being in liquid communication with said source tank and, said secondary process liquid discharge outlet being in liquid communication with said destination tank;
• d) said secondary process being positioned above an interior bottom surface of said source tank, such that liquid will flow by gravity fed drainage out of said source tank, and into said secondary process liquid inlet;
• e) said secondary process being positioned above said destination tank, such that liquid will flow by gravity fed drainage out of said secondary process liquid discharge outlet, and into said destination tank liquid entrance opening;
• f) a means responsive to liquid level height in said source tank, for increasing and decreasing liquid flow rate into said source tank liquid entrance opening as liquid level height in said source tank falls below and rises to a predetermined height;
• and
• g) a means responsive to liquid level height in said destination tank, for increasing and decreasing liquid flow rate into said source tank liquid entrance opening, as liquid level height in said destination tank falls below and rises to a predetermined height.