Six modular planter boxes with varying soil combinations will continue the water purification process within the greenhouse. Each box will contain a different combination of soil, sand, gravel, etc. contained within a removable tray so that experiments can be easily conducted on the purifying capablilities of different combinations of materials. Water quality samples will be taken from the exit drain of each box to determine the effectiveness of the chosen materials
The modular boxes are 4 ft X 20 ft X 1.5 ft and are designed to be open shallow containers so that the surface area to volume ratio is high. Tropical plants will be grown in soil directly above the removable trays.