Working No3 Back To Figure Out Nh3 Production

[anon02]

Would it be feasible to divide NO3 levels by 3.6 to get some idea of the NH3 production over a set time

If I started off with zero nitrate and at the end of 10 days I measured 36ppm nitrate, could I assume that the tank produced an average of 1ppm ammonia per day ?

 

[Aqua Tom]

Over to you Waterdrop

 

[Curiosity101]

I actually thought the relationship was 1 : 1 : 1 ... if you balance the chemical forumlas it is anyways...

So the tank would be creating 5.1ppm a day. Which tbh is inline with the fishless cycling guide really... (which also makes me think it's 1:1:1)

Cause in the qualifying week it should be able to deal with 4-5ppm of ammonia in 12 hours rather than 24hours. And it's meant to give you plenty of scope to avoid any ammonia and/or nitrite spikes after fish are added.

Actually having said that... it's a 1 : 1 : 1 relationship with regards to reacting. But in solution 1 molecule of NH3 would give a different ppm value to 1 molecule of NO3... so actually yeah I reckon your idea of dividing by 3.6 sounds good presuming it's taken into account molecular weight.

 

[Skins]

I agree with you Tom this one is for WD. I'm looking forward to the replies on this subject.

Skins.

 

[Skins]

I actually thought the relationship was 1 : 1 : 1 ... if you balance the chemical forumlas it is anyways...

So the tank would be creating 5.1ppm a day. Which tbh is inline with the fishless cycling guide really... (which also makes me think it's 1:1:1)

Cause in the qualifying week it should be able to deal with 4-5ppm of ammonia in 12 hours rather than 24hours. And it's meant to give you plenty of scope to avoid any ammonia and/or nitrite spikes after fish are added.

Actually having said that... it's a 1 : 1 : 1 relationship with regards to reacting. But in solution 1 molecule of NH3 would give a different ppm value to 1 molecule of NO3... so actually yeah I reckon your idea of dividing by 3.6 sounds good presuming it's taken into account molecular weight.

Would i be right in thinking this is why it takes longer for the n-bacs to colonise.

Skins.

 

[Aqua Tom]

I admit it, I am totaly lost.

 

[Curiosity101]

Would i be right in thinking this is why it takes longer for the n-bacs to colonise.

Now that definitely is a WD question! lol.

I can vaugely do chemistry... although it's been a couple of years since finishing my A level in it.
But I'm no fishless cycling expert!

However from a biologists point of view I'd say probably not. It's likely that either A) They're just a slower growing type of bacteria or B)The reaction yields less energy in comparison so they can't grow as fast.

I'm going with B as the most likely.

 

[Doc7]

Might be wrong but here is my first shot at aquarium chemistry:

Assume a 1 L tank and with these concentrations assume 1 ppm is equivalent to 1 mg/kg or 1 mg / L.

Ammonia to Nitrite:

2NH3 + 3 O2 -> 2NO2- + 2H+ + 2H2O

1 :1 molar ratio of NH3 to NO2

1 ppm NH3 = 1 mg NH3 / L H2O
NH3 = 17.031 g/ mol

1 ppm = .001 g NH3 / 17.031 g/mol = 5.8717 * 10 ^ -5 mol NH3 in a L of water

Converted to 5.8717 * 10 ^ -5 mol NO2, @ 46.01 g/mol = 0.002702 g = ~2.702 ppm NO2

So Nitrite to Ammonia is a 2.702 : 1 Ratio

Nitrite to Nitrate
2NO2- + O2 -> 2NO3-

1 : 1 molar ratio so full conversion results in 5.8717 * 10 ^ -5 mol NO3, @ 62.005 g / mol = 0.003641 g = ~ 3.64 ppm NO3

So ratio is

1 ppm NH3 : 2.702 ppm NO2 : 3.64 ppm NO3 by my calculations


So yes I figure you are correct that it is 1 ppm ammonia per day in your example.





edit: of course the easy way, upon seeing that the calculations are all 1:1 molar ratios would be that you just divide molar mass. i guess you guys actually already knew all this. oh well, now i know for myself too

 

[waterdrop]

Yes, without looking for mistakes, it looks like Doc7 has got all the chemistry right there. We quote the 2.7x and 3.6x multiplication factors all the time (1ppm of ammonia is converted by the A-Bacs to roughly 2.7ppm of nitrite(NO2) and 3.6ppm of nitrate(NO3))

And yes, this is the main reason why it takes a lot longer to grow a large enough colony of N-Bacs as compared to A-Bacs, because you need enough N-Bacs to convert a lot more nitrite to nitrate. The other thing though is that the Nitrospira spp. (N-Bacs) are thought to have a slightly slower reproductive cycle I believe, than the Nitrosomonas spp. (A-Bacs.)

Now I tend to be overly pessimistic about things like this, so maybe the scientists will correct me but to my thinking, this rarely works out in practical ways. The chemistry we're describing is something that chemists do in isolation, not in biological systems. In our systems we are not doing chemistry, by definition. What are bacteria made of? Lots and lots of really complicated macromolecules, inorganic molecules and everything in between! Is there other stuff in that tank? Sure! Is there stuff that might react with or absorb the things we're talking about measuring? Sure! So our tests might not find some of our products.

Then what if we go beyond a bare-tank fishless cycle? What if we put plants in there? A huge difference. Plants will take in these things, ammonia the most, nitrates next most and a few plants will even take in small amounts of nitrite, but it's rare. All those things vary a lot by which species of plant and the health of the plant and it's environmental conditions.

And what about trying to match a tropical fish bioload with a production nitrate measurement in ppm? Well, if we took a shoal of one species at a time in a bare tank and did some measurements over time it might be interesting! But I don't know that it would change our behavior with fishless cycling because of course we want the "robustness" of the bacterial colonies to be as developed as possible and that's very different from simply having colonies that match a bioload in my opinion. We want to ensure drop-down at the first stocking.

~~waterdrop~~

 

[anon02]

Thanks for all the interest guys,

Doc 7, that`s exactly how I worked it out in my head

This was just a whimsical question, thought up whilst I was waiting for my coffee to cool. I can`t think of a practical use, not even in a "rule of thumb" sense. As you say WD there are too many variables in a tank situation

 

[Geoff-]

And yes, this is the main reason why it takes a lot longer to grow a large enough colony of N-Bacs as compared to A-Bacs, because you need enough N-Bacs to convert a lot more nitrite to nitrate. The other thing though is that the Nitrospira spp. (N-Bacs) are thought to have a slightly slower reproductive cycle I believe, than the Nitrosomonas spp. (A-Bacs.)

I have this, and also that Ammonia inhibits/damages N-bacs so whenever you have Ammonia in your tank the N-bacs will die off. For me, the A-Bac cycle took about the same amount of time as N-bac, but the N-bac was actually more frustrating because of the 2.7x production rate of toxin which meant I had to do frequent and large water changes (I skipped a couple once and 2 fish promptly went wobbly, then died a few days later while the others came good with resumed water changes).

 

[waterdrop]

I have never heard that the types of ammonia levels we see in either normal or cycling tanks would damage N-Bacs. We would not see tanks being successfully fishless cycled if this were the case. WD