Swimming Pool Treatment
| Problem | Possible Causes | Solution |
| Elevated pH (alkaline) | Alkaline water supply | Addition of acids adjuvants (e.g. dilute hydrochloric acid 20 times or appropriate commercially available products) |
| Elevated pH (alkaline) | The disinfectant used is alkaline | Consider the use of an acidic disinfectant |
| Low pH (acid) | Acidic water supply | Proceed to the addition of alkaline adjuvants (e.g. soda, sodium carbonate or appropriate commercially available products) |
| Low pH (acid) | The disinfectant used is acidic | Consider the use of an alkaline disinfectant |
| Unstable Ph | Water is not buffered | alkalinity levels are too low | Check and increase alkalinity |
| Ph hard to change | Water is too buffered | alkalinity levels are too high | Check and decrease alkalinity |
| Chlorine too high | Overdose of chlorine | Increase water renewal/dilution | If the chlorine levels rare above mg/L 10, you may use Sodium Thiosulphate or hydrogen peroxide to reduce them. This procedure must be done with the pool closed. The dechlorination of a pool should not be a routine solution, ideally, you should resort to dilution. More information in the Hints and Tips section |
| Cloudy and dirty water | Too much use | Inadequate filtration | Reduce use and/or increase water renewal / Check filtration, flow rates and backwash |
| Cloudy water | Precipitated salts associated with hardness | Air inlet or coagulant dosage | Check and correct, if necessary, pH, alkalinity and hardness | Check for possible air inlets in the filters and pump | Recalculate the dosage of coagulant |
| Cloudy and coloured water | Algae and sunlight, insufficient filtering | Increase the level of chlorine, perform a backwash. Use an algaecide |
| Growth of viscous material on the walls and floor of the pool | Algae and sunlight, insufficient filtering | With the pool closed, brush and/or vacuum the algae, increase the level of chlorine, perform backwash and use an algaecide |
| Water has a bad taste or smell / irritating to eyes and throat | High combined chlorine | Incorrect pH | Check combined chlorine. Eventually, dilute or correct the free chlorine / Check and correct, if necessary |
| Microbiological contamination (bacteria coliforms, Escherichia coli, Enterococci) | Bacteria naturally present in the environment and/or from contamination by faeces and/or blood and/or mucous and/or skin | Due to high concentrations of disinfectant, this procedure should be done with the tank closed: carry out shock treatment by adding enough amount of disinfectant to achieve a concentration of 20 mg/L Cl2 during 8 hours (or 40 mg/L Cl2 for 4 hours) |
| Contamination with Pseudomonas aeruginosa and Staphylococcus | Bacteria naturally present in the environment and often present in the swimmers | Low levels of disinfectant and/or insufficient backwashing | Overflow pool before performing the previously mentioned chlorine treatment. |