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I have a couple of new questions on the Nitrification process.

As I have stated before I am new to chemistry.

1. Does the API Freshwater Test Kit measure free or combined Nitrates?

When the test indicates 0 nitrates, is this a good thing, or does it indicate that we no longer have adequete nitrates to support the plant load, or is that part of the unknowns re combined ions.

2. I have encountered no information regarding upper limits on nitrate levels until today when I referred to "Wiki Nitrates, which indicates that nitrates > 30 PPM is toxic to marine life.

My own limited experiance has shown that upon reaching high level nitrates and adding a plant load, the nitrate levels have been slowly decreasing though still >0. I would conclude that a nitrate level of zero in a cycled system, would indicate excessive plant load. 

 

Marine toxicity

Sea surface nitrate from the World Ocean Atlas.

In freshwater or estuarine systems close to land, nitrate can reach high levels that can potentially cause the death of fish. While nitrate is much less toxic than ammonia,[12] levels over 30 ppm of nitrate can inhibit growth, impair the immune system and cause stress in some aquatic species.[13] However, in light of inherent problems with past protocols on acute nitrate toxicity experiments, the extent of nitrate toxicity has been the subject of recent debate.[14]

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Replies to This Discussion


1. Does the API Freshwater Test Kit measure free or combined Nitrates?

 

Robert, I think you might be confusing Nitrates with Ammonia... which can be measured as "free" ammonia, or "Total Ammonia Nitrogen"... referred to as TAN...

 

The API ammonia test.... measures TAN...

 

When the test indicates 0 nitrates, is this a good thing, or does it indicate that we no longer have adequete nitrates to support the plant load, or is that part of the unknowns re combined ions.

 

Not sure what you mean by "part of the unknowns re combined ions"....

 

My own limited experiance has shown that upon reaching high level nitrates and adding a plant load, the nitrate levels have been slowly decreasing though still >0. I would conclude that a nitrate level of zero in a cycled system, would indicate excessive plant load.

 

A nitrate level of zero is not uncommon in a mature and balanced system... and doesn't necessarily indicate an inadequacy of nitrate provision to the plants...

 

Nitrates are continually being produced within the system... and a zero level may just mean that the plants are consuming all that is available...

 

Slowed plant growth, or signs of Nitrogen deficiency... would indicate insufficient nitrate availability...probably suggesting the need for additional fish...

But this is almost never the case... (usually most people have too many fish... )

 

2. I have encountered no information regarding upper limits on nitrate levels until today when I referred to "Wiki Nitrates, which indicates that nitrates > 30 PPM is toxic to marine life.

 

Levels of 30ppm are often quoted in references to marine aquaria systems.. for ornamental fish and corals...

 

But the lowest reported aquacultural references to nitrate toxicity for freshwater fish are 450ppm ... for blugill...

 

With most other fish having level up to, and beyond 1000ppm...

 

The "fry" of some species, particularly trout.... are more susceptible.. and prolonged levels above 30-100ppm are not recommended..

Thanks for responding. I will get my arms around this.



RupertofOZ said:


1. Does the API Freshwater Test Kit measure free or combined Nitrates?

 

Robert, I think you might be confusing Nitrates with Ammonia... which can be measured as "free" ammonia, or "Total Ammonia Nitrogen"... referred to as TAN...

 

The API ammonia test.... measures TAN...

 

When the test indicates 0 nitrates, is this a good thing, or does it indicate that we no longer have adequete nitrates to support the plant load, or is that part of the unknowns re combined ions.

 

Not sure what you mean by "part of the unknowns re combined ions"....

 

My own limited experiance has shown that upon reaching high level nitrates and adding a plant load, the nitrate levels have been slowly decreasing though still >0. I would conclude that a nitrate level of zero in a cycled system, would indicate excessive plant load.

 

A nitrate level of zero is not uncommon in a mature and balanced system... and doesn't necessarily indicate an inadequacy of nitrate provision to the plants...

 

Nitrates are continually being produced within the system... and a zero level may just mean that the plants are consuming all that is available...

 

Slowed plant growth, or signs of Nitrogen deficiency... would indicate insufficient nitrate availability...probably suggesting the need for additional fish...

But this is almost never the case... (usually most people have too many fish... )

 

2. I have encountered no information regarding upper limits on nitrate levels until today when I referred to "Wiki Nitrates, which indicates that nitrates > 30 PPM is toxic to marine life.

 

Levels of 30ppm are often quoted in references to marine aquaria systems.. for ornamental fish and corals...

 

But the lowest reported aquacultural references to nitrate toxicity for freshwater fish are 450ppm ... for blugill...

 

With most other fish having level up to, and beyond 1000ppm...

 

The "fry" of some species, particularly trout.... are more susceptible.. and prolonged levels above 30-100ppm are not recommended..

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