This tank is based on a tanks which stood at Demondrille and the southern end of Coffs Harbour yard.  However, this size of tank was common and water softening plants of Departmental design were often used to treat river water to improve its use for steam locomotives.  It is similar to other tanks at Kempsey, Bargo, Penrith and Griffith, among many others. 
Alkalinity plants of this design were also quite common with examples at South Grafton, Albury, Junee, Penrith, Gloucester and elsewhere. 
The model as supplied contains etched brass and nickel silver components to assemble the tank and stand, with additional 3d-printed or exoxy moulded parts for the alkalinity plant and tank.  Detailed, full-colour instructions are available to download.