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Tech Tip #98-7

Bio-Cord Reactors/Water Treatment - For use with Trout Farming Applications

Generally in fish farming applications the volume of ammonia is usually less than 1ppm. Therefore the concentration of NH3 (ammonia) must be less than 0.002-0.003 ppm.

In trout farming applications it is the water becoming turbid after rain that affects the fish the most, rather than the ammonia.

The cause of the suspended solids in the water is the waste from the fish breaking into pieces and becoming suspended in the water. Possibly the waste from the fish is also causing the contamination.

The following is an experiment to prove the above theory:

  • Average weight of each trout is 20g.
  • The findings are as follows, with the water being reused three times.

Looking at the graph it seems that as the ammonia increases the fish's growth is reduced. The pH in this experiment is 6.4-6.8 and water temperature is 17.8-19.4oC.

Ammonia concentration is 0.001 ppm even in section IV. It must be the level of NH3 that acts as a poison.

According to this experiment it is not the ammonia that negatively affects the fish it is the suspended waste in the water.

According to another experiment nitrogen and organic compound from precipitated waste flows quickly into the water.

In addition we have to be careful the DO (dissolved oxygen) should be reduced to less than 3.5ml / 1.

When looking at this graph, it seems that as the amount of ammonia increases the falling growth of fish.

PH in this experiment is 604 - 6.8 and water temperature is 17.8 - 19.40C.

NH3 concentration is 0.0001 ppm in IV section, the lowest place.

That is why it must not be the level of NH3 that acts as a poison.

By those experiments, it is not the ammonia that brings the fish influence, but the suspended solids in the water.

According to another research, nitrogen and organic compound from precipitated waste flows unexpectedly quickly into the water.

It is better to remove the waste as quickly as possible.

In addition, we have to be careful less DO (dissolved oxygen) should reduce less that 3.5mL / L. If it reduces feed, efficiency also reduces.



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