| Problem | Possible Cause | Check / Remedy |
| Algae growth. |
Sanitiser level low. Sunlight dissipating sanitiser. High pH reducing sanitiser effectiveness. Not using preventative Algaecide. |
Ensure sanitiser / cyanuric acid levels are adequate throughout the pool. Reduce pH to recommended range of 7.2 – 7.6, Use maintenance algaecide dose. |
| Calcium hardness too high / scale formation. |
Build-up of calcium salts. |
If mains water has a lower calcium level, dilute the pool. Add a monthly dose of Stain & Scale Inhibitor. |
| Calcium hardness too low / pool grouting soft or eroding. |
Soft mains water supply. |
Increase calcium hardness level to a minimum of 200ppm. |
| Cloudy water. |
Build-up of swimmer pollution. Inadequate sanitiser levels. Cyanuric acid too high. Ineffective filtration. Water not ‘balanced’ correctly. |
Check sanitiser levels and if necessary shock dose the pool. Dilute to reduce cyanuric acid levels. Filter media needs cleaning / changing. Check water balance and adjust if required. |
| Chlorine level low / difficult to maintain. |
Lack of sanitiser / cynauric acid. High bather load / prolonged hot weather. |
Increase sanitiser dose and if necessary adjust cyanuric acid levels. More frequent shock dosing may be required. |
| Chlorine reading is zero using test kit despite chemical additions. |
Chlorine level may be too high causing test reagents to bleach. Chlorine demand (very high build-up of pollutants). |
Allow sanitiser level to drop naturally / lower using Chlorine Reducer or dilute by partially draining and refilling. Continue to shock dose pool water if over-chlorination is not the cause. |
| Chlorine level is high |
Over chlorination |
Allow sanitiser level to drop naturally, lower using Chlorine Reducer or dilute by partially draining & refilling. |
| Green staining |
Copper in pool water precipitating |
Test copper level. Check water balance and adjust if necessary. Add an initial dose of Stain & Scale Inhibitor. For sand filters, also use Aquasparkle Tabs or Flockfix Cartridges to aid with copper removal. |
| pH level high |
High pH of mains water. Alkaline shock treatment being used. |
Regular doses |
