Nitrate being converted into Nitrite?

[mark4785]

My aquarium currently contains 4 albino corydoras which are all continually gasping for air. I have tested my ammonia and nitrite levels and the former is at 0 ppm while the latter is between 0 and 0.25 ppm.

I'm finding that every time I dose the aquarium with nitrate (a fertiliser for the plants), the drop-checkers are turning yellow (indicating very high co2) and the nitrite level is going up to 0 - 0.25 ppm.

I have come across an article on the internet ( Koi, Goldfish & Pond Health Considering Nitrite, Ammonia reduction to Nitrite - Water Quality and Fish Health ) which indicates that under hypoxic conditions (low oxygen) nitrate can be converted back into nitrite by a certain strand of bacteria. Is this what is happening in my aquarium? If it is, why would the tank become hypoxic only after introducing the nitrate fertiliser?

I have been using the said nitrate fertiliser for about 5 years and used it today on a separate tank; the fish in there are not hypoxic and have been solidly healthy for as long as I can remember.

I'm really confused as to what to do. I was previously advised by the UKAP community to plant-up and avoid the liquid ammonia cycle as the latter was ann avenue which I could take for healthy plants and fish; this is something I chose to embrace and now the fish are really suffering at this moment as it would seem that my nitrate fertiliser is being converted into nitrite by some sort of rogue bacterium in the filter.

 

[NatureBoy]

drop checker indicates pH strictly and can rise and fall depending on CO2, and other chemicals that add to the acid profile of the water...another of which can be ammonium nitrate, which can form nitric acid. It begs the question what brand of nitrate are you using and how much?

 

[geoffbark]

As nature boy says which fert are you using. If it does contain ammonium nitrate, then the ammonia will be causing the problem as it is converted into nitrite.

I would also consider increasing O2, this can be done by air stone. Power head. Or more water surface movement.

You may find that you will use more CO2 as you increase O2.

 

[mark4785]

drop checker indicates pH strictly and can rise and fall depending on CO2, and other chemicals that add to the acid profile of the water...another of which can be ammonium nitrate, which can form nitric acid. It begs the question what brand of nitrate are you using and how much?

I acquired the potassium nitrate in salt form from Fluidsensor; I add it to RO water. As said in my first post, I've been using it for 5 years and its never presented a risk to the fish in my other aquarium.

 

[NatureBoy]

I acquired the potassium nitrate in salt form from Fluidsensor; I add it to RO water. As said in my first post, I've been using it for 5 years and its never presented a risk to the fish in my other aquarium.

shouldn't be a problem then if its plain old potassium nitrate.

So you inject CO2 given you have a drop checker? could it just be CO2 that is causing the drop checker to turn yellow and the fish to gasp for breath?

 

[mark4785]

shouldn't be a problem then if its plain old potassium nitrate.

So you inject CO2 given you have a drop checker? could it just be CO2 that is causing the drop checker to turn yellow and the fish to gasp for breath?

No as the drop checker has turned yellow without any co2 injection at all. It only turns yellow after adding the phosphate and potassium nitrate. After adding these ferts, the nitrite increases slightly but this never happens when adding the same ferts to a separate tank. Why is there a discrepancy happening here?

 

[NatureBoy]

I think I'd need to see pics / vid of the tank + info about the lights / filter / substrate etc to get a better overall feel for the health of the tank. What plants have you got etc?

At the end of the day the nitrate is there to feed the plants, if it's not being taken up then it may well end up as a food source for bacteria. If that's the case perhaps adding nitrate is not serving a beneficial purpose in the quantities / in isolation of all other factors.

You have to think hi tech / low tech and follow one of these methodologies as a start point. What is your goal through adding nitrates?

 

[geoffbark]

+1 nature boy

We need more info including pics of your tank.

Dosing schedule, lighting period, filtration etc.

The drop checker maybe turning yellow due to Co2 build up From plants and no oxygen being added. No surface movement etc.