Total Dissolved Solids
The cumulative concentration of all dissolved matter in pool water.
Definition
Total dissolved solids (TDS) is the sum of all inorganic and organic substances dissolved in pool water — minerals, chemicals, byproducts of sanitization, bather waste, and more. TDS increases over time as chemicals are added and water evaporates. High TDS can reduce chemical effectiveness, cause foaming in hot tubs, and contribute to cloudy water. The only remedy is partial or full water replacement. In hot tubs, TDS above 1,500 ppm over the baseline is a standard trigger for water change.
Quick Facts
- Ideal Range
- Below 2,000 ppm (pools); below 1,500 ppm above baseline (spas)
- Units
- ppm
- Also Known As
- TDS, total dissolved solids, dissolved solids
Relationships
Incoming Relationships
- related to ← Water Replacement