For lack of a better place, the Instructions project section gives a detailed description of the system. Last update September 25, 2018.
If you would like more information on the custom Raspberry PI board that controls the system, there is another project that covers it here.
This links to an interactive plot of actual EC/pH/Temperature data which is on display at plot.ly. Hover near the top of the plot for the controls. Click and drag on the plot to zoom a region. Drag the center of the tic labels to move the data. Drag on the ends of the tic labels to change the displayed range. This is the exact same type of plot that is on the web page served by the Raspberry PI controller.