Hardness vs TDS

There is no correlation between the hardness and total dissolved solids content of the different water collection points.

This would mean that the bulk of the total dissolved solids did not consist of hardness-causing cations and anions like Calcium, Magnesium, Carbonates and Bicarbonates.

To prove this further, the hardness of our control (Tank before Pond) was one of the higher ones despite having a TDS concentration of 0mg/L.