All too often we see the damage that unbalanced water can cause when it comes in contact with concrete, grouting and metals like copper and steel. Water can either corrode such surfaces or deposit a white film or crusty, coarse substance called scale. The two types of unbalanced water conditions are corrosive and scaling.
Corrosive water is "aggressive" and attempts to dissolve concrete and metals, pitting concrete and destroying steel filters and copper heat exchangers. A tell-tale sign of corrosive water is staining, which is the deposit on the pool's surface of colored metal salts of iron (brown) or copper (blue/green/grey/black). Scaling water does the opposite. It attempts to deposit or precipitate calcium carbonate out of solution, causing a white film or rough, unsightly deposits on pool surfaces, and possibly plugging the filter and circulation piping.
To keep your pool water in balance and avoid unnecessary and costly repairs you must control the parameters that determine water balance. The factors are pH, calcium hardness, total alkalinity, temperature and total dissolved solids (TDS). The main focus should be on pH, calcium hardness and total alkalinity.
pH is a scale of measurement that was invented in the early 1900s for checking the acidity of water when brewing beer. pH is measured on a scale from 0-14 and can be tested by a number of test kits
. pH is neutral at a measurement of 7.0. Below 7.0, the water is acidic and above the water is alkaline (basic). The recommended pH for pools is 7.5 which matches the pH of the human eye.
|Low pH Pool Problems
- pitting of concrete
- metals dissolve
- surface staining
- chlorine loss
- vinyl wrinkles
- skin/eye irritation
|High pH Pool Problems
- white film/crusty deposits
- plugged filters
- reduced circulation
- cloudy pool
- chlorine inefficiency
- skin/eye irritation
Total alkalinity is the measure of the ability of water to resist changes in pH. Total alkalinity acts as a "buffer" to the pool water from wide variations in pH. It is the governor of pH and is a major factor that affects water balance.
A buffer is a chemical system that resists change when acid (such as pH decreaser
) or bases (such as pH increaser
or alkalinity booster
) are added to the swimming pool. Water that has no buffering ability has a very low alkalinity and is subject to rapid swings in pH levels when small amounts of acid or base products are added. The result is highly unbalanced water that can cause damage to light rings, stainless steel ladders, copper heat exchangers and concrete pool surfaces.