pH Range

Interpretation

Remarks

1.0 - 4.9

Extremely acidic

Toxic to fish

2.0 - 6.6

Moderately acidic

Low productivity

6.7 - 9.9

Suitable H⁺ ion

Desirable for fish (High productivity)

9.1 - 11.0

Moderately Alkaline

Low productivity

11.1 - 14.0

Extremely Alkaline

Toxic to fish