Fish, chitin, and chitosan production 307
b) To avoid fish toxicity, the NH 3 concentration in the fish pond water
should be less than 1 mg/L. If due to the algal-bacteria symbiotic
reactions, the pH of the fish pond water becomes 9 at 3 pm., determine
whether there will be NH 3 toxicity to fish or not. If so, suggest method
to alleviate this problem. Figure 6.9 shows the effects of pH on NH 3 +
NH 4 + concentrations.