opening 14 coaxially aligned with each of the cell plugs 13 the valve members 23 include a transparent lower conduit housing 27 as noted above orthogonally mounted and in fluid communication with the central horizontal conduit housing 25 the lower conduit housing 27 includes a tubular upper housing 28 that includes a valve opening 32 therethrough with the valve opening 32 defining a diameter less than that of an internal diameter defined by the tubular upper housing 28 a valve head 31 is positioned between the valve opening 32 and the upper housing 28 to selectively enable directing of fluid from the central conduit housing 25 through the lower conduit housing 27 the valve head 31 includes a threaded stem 33 threadedly received in threaded communication with companion threads formed through an upper surface of the conduit housing 25 the threaded stem is directed upwardly and exteriorly of an external wall of the central conduit housing 25 with a spring member 34 captured between the exterior wall surface of the central conduit housing 25 and a bottom surface of a valve handle 35 to maintain positioning of the valve head 31 in an open or closed orientation relative to the valve opening 32 the spring 34 thereby serves as a friction detent to maintain a relative rotative position of the threaded stem 33 relative to the opening 32 upon manual rotation of the stem 33 the transparent lower conduit housing 27 is coaxially aligned and in fluid communication with a hollow truncated conical valve housing 29 that is secured within a sealing relationship relative to the openings 14 a check ball opening 36 is formed through a floor of the conical lower housing 29 and is of an opening.