What Are the Dangers of High or Low pH Levels in Water?

The pH level is a measure of the hydrogen ion content in water. The higher the concentration, the more acidic the water. The lower the concentration, the more basic the water. If the water pH level is too high or too low, fish cannot survive.

  1. History

    • The pH scale range from 0 to 14: 0 is extremely acidic, and 14 is extremely basic (alkaline). The pH scale is logarithmic. Each whole digit increment represents a tenfold increase in hydrogen ion concentration.

    Significance

    • Pure water has a pH of 7. Water with dissolved gases, minerals and chemicals has a pH range of 5.5 to 8.5. Freshwater fish generally live in water with a pH range of 5.5 to 7.5. Saltwater fish generally live in water with pH 8.0. Each species has a specific range within the general range.

    Effects

    • If pH levels get to high, ammonia toxicity increases. The water hardness also increases. There are more minerals dissolved in the water. This creates a buffer effect, which prevents reduction in pH. If pH levels get to low, water can leach metal ions from plumbing and filters.

    Prevention

    • To prevent changes in pH, monitor water regularly with pH strips. If the pH is too high, add peat to the filter to reduce pH. If the pH is too low, add mineral salts like calcium to increase pH.

    Considerations

    • Many species of fish can only breed if the pH is within a specific range. Frequent water changes and gravel maintenance can help maintain a stable pH.