What is TDS?
A. TDS (Total Dissolved Solids) is the term given to the sum total level of substances dissolved in the water. Example, sea water has TDS level of about 35,000 ppm, (mostly salt). Most Melbourne suburbs have about 40-60 ppm (or milligrams per litre), Sydney about 130 ppm. Sth Aust. and WA have extremely high TDS. Only Deioniser, Reverse Osmosis and Distillation remove TDS; the result: fully purified water. The water coming out of other types of purifiers eg. a Carbon Filter, will have the same (or almost) the same TDS as the tap water! A simple test with a TDS meter will reveal this.
The sum total of all the dissolved material in the water is called “total dissolved solids” or TDS. Sources of TDS in the water include disinfectants, balance chemicals, calcium hardness, source water, bather waste, algaecides, total alkalinity, wind blown dust and dirt, phosphates, nitrates, and sulfates. TDS buildup is inevitable. Every time you add chemicals to the water, the TDS increases. Even adding makeup water to the pool increases TDS. When water evaporates, only the pure water leaves the pool and all material that was dissolved in the water remains behind. This builds up over time, increasing the TDS. The ideal range of TDS is from 1000 to 2000 PPM, and the maximum level is 2500 PPM to 3000 PPM. There is no way to reduce TDS chemically. You must drain or partially drain the pool and replace with fresh water.
Total Dissolved Solids, the total measurement by weight of all solids that are dissolved in water. The dissolved solids in water are primarily calcium and magnesium and would not be a measurement of contamination. Tests that measure the conductivity of water (often used by companies selling reverse osmosis systems) only give a rough estimate of dissolved solids and should not be viewed as an indicator of water quality.
