Glossary

soft water

Water containing low concentrations of mineral salts, especially calcium or magnesium.

Used in 80 species profiles

alkalinity
Measure of the buffering capacity of a given water body, i.e. its capacity to neutralize acids and bases thereby maintaining a fairly stable pH. Water containing compounds, such as bicarbonates, carbonates, and hydroxides has a stronger such capacity and is referred to as hard water, while water lacking or deficient in them is termed soft water. Soft water aquaria tend to be susceptible to pH crashes if not maintained correctly.
total dissolved solids
Measure of the total concentration of both organic and inorganic, microscopic particles suspended in a given liquid. Usually applied only to freshwater systems and measured using a conductivity or total dissolved solids meter with results expressed in units of mg per unit volume of water (e.g., mg/L) or parts per million (ppm). Soft water with low pH generally has low levels of total dissolved solids whereas harder water with higher pH tends to contain correspondingly increased concentrations. Often abbreviated to TDS.