Migthegreek - Fishless Cycle Log

[waterdrop]

How much nitrite am I waiting for to reduce my ammonia dosage to 2ppm? Do I need to wait for it to go off the scale? (5+ ppm)

Yes, wait until its going off the scale.

migthegreek, on 16 November 2009 - 08:27 AM, said:

When I add more ammonia, what amount am I going for? I read in the beginners' Fishless Cycle thread 3-4ppm but you recommended someone add 2ppm during the nitrite spike or something in a different thread. Can you explain this for me?

JustFrozen replied: this is a great question. a lot of times we're told what to do but not necessarily why, and this is something i've been wanting to know myself, as i'm currently in the nitrite spike phase. my understanding of it is that during the nitrite spike phase, the only goal is to get enough nitrite-processing bacteria to get the level of nitrite down to zero. if you keep dosing the full amount of ammonia, it's only going to keep the nitrite off the chart for longer. really what you want is to just give enough ammonia so the ammonia-processing bacteria dont die off. it probably wont hurt the cycle to add the full amount but there's already plenty of nitrite in the water without adding a full 5ppm of ammonia every day, so i guess you are just delaying the day that you will see the nitrite hit zero. WD or OM or someone please let me know if this is correct

JF, I don't think we ever attempted to answer the deeper question you had here of "why?" The answer is as follows: Any time your test finds measurable nitrite(NO2) it of course means there's more than enough food to "grow" that particular species-specific colony. So even a little nitrite would be sufficient to help the N-Bac colony get larger. But since the A-Bacs put out 2.7ppm NO2 for every 1ppm of NH3, we have excess NO2 sitting around that's not really needed. The too-small N-Bac colony will, eventually, work its way through the excess but as it does that it will be further multiplying it (x3.6) and so the final nitrogen product, NO3(nitrate), will always be in excess.

The thing about nitrate ion(NO3-) is that when it is in solution in water, it will exist in its different resonance structures and although about 93% of it will be in the ionic state with a minus charge, about 7% will find a naked hydrogen proton (H+) and form HNO3, which is Nitric acid, a very powerful acid (yes, the wicked looking stuff that fumed in chem class!) Of course, its only a tiny amount and is distributed in a lot of water, but nonetheless it has a powerful ability to lower the pH of the tank water. This is the reason that nitrification lowers pH any time it is in process (which is always, to some extent, in a tank with a biofilter.) During fishless cycling, when we (on purpose) simulate a fish stocking that's larger than the tank can properly handle, the acidification from excess nitric acid can be quite pronounced and will nearly always drop the pH to the point where the autotrophic bacteria will stop processing, in tanks with insufficient KH.

~~waterdrop~~

 

[Deleted member 55926]

Any time your test finds measurable nitrite(NO2) it of course means there's more than enough food to "grow" that particular species-specific colony. So even a little nitrite would be sufficient to help the N-Bac colony get larger. But since the A-Bacs put out 2.7ppm NO2 for every 1ppm of NH3, we have excess NO2 sitting around that's not really needed. The too-small N-Bac colony will, eventually, work its way through the excess but as it does that it will be further multiplying it (x3.6) and so the final nitrogen product, NO3(nitrate), will always be in excess.

The thing about nitrate ion(NO3-) is that when it is in solution in water, it will exist in its different resonance structures and although about 93% of it will be in the ionic state with a minus charge, about 7% will find a naked hydrogen proton (H+) and form HNO3, which is Nitric acid, a very powerful acid (yes, the wicked looking stuff that fumed in chem class!) Of course, its only a tiny amount and is distributed in a lot of water, but nonetheless it has a powerful ability to lower the pH of the tank water. This is the reason that nitrification lowers pH any time it is in process (which is always, to some extent, in a tank with a biofilter.) During fishless cycling, when we (on purpose) simulate a fish stocking that's larger than the tank can properly handle, the acidification from excess nitric acid can be quite pronounced and will nearly always drop the pH to the point where the autotrophic bacteria will stop processing, in tanks with insufficient KH.

Crikey, thanks for the chemistry lesson, waterdrop! I'll try to digest it!

 

[Deleted member 55926]

Day 8

Ammonia = 1.5 (dosed up to 4.0 last night)
Nitrite = 0.25 (climbing very slowly)

 

[OldMan47]

That sounds like a nice start.

 

[Deleted member 55926]

So how long until the nitrite is likely to spike, based on my ammonia hitting 0 after about a week? And I keep dosing back to 4ppm ammonia every time it drops, until the nitrite spike, right?

Sorry for the millions of questions all the time, but I just want to get everything right and ensure I learn about everything.

 

[OldMan47]

It should only be a day or two before you have a hard time quantifying the nitrites.

 

[Deleted member 55926]

Day 9

Ammonia = 0 (dosed up to 4.0 last night)
Nitrite = 0.25

Well it's been 3 or 4 days since nitrite started appearing, and it has stopped at 0.25ppm - no change since yesterday. I don't understand, because based on this:

the A-Bacs put out 2.7ppm NO2 for every 1ppm of NH3

Shouldn't there be tons of nitrite in the tank, seeing as at least 4ppm NH3 has been processed since it hit 0?

 

[OldMan47]

If you are regularly processing ammonia from 4 ppm to zero in a day, I would be expecting to see something by now in nitrites. Be aware that nitrite tests can show a color that looks almost like a zero but means that the amount is so high the test cannot get a good color. There are various descriptions of it in other threads but the essence of it is that when you first add the drops, even before mixing, you get a color response that seems to disappear when you mix in the test chemical. It never does show any color on the chart until the levels come back down. Is it possible that you have slipped into a stage that is responding this way?

 

[Deleted member 55926]

Day 10

Ammonia = 0
Nitrite = 0.5

Well the ammonia is easily being processed in 24 hours now, but I don't know what to do about the nitrite. It has gone up slightly today, and is definitely reading 0.5, where yesterday it was definitely at 0.25.

Any more detailed info on how I can tell if it's off the chart? The drops are the blue of 0 when they first go in, then slowly turn to the purple of 0.5, but I don't know why the colour would've changed gradually over the course of the last 3 or 4 days. I would've thought that it shows the same colour every time if it's off the chart.

 

[Deleted member 55926]

Day 11 - AM

My tank is now processing 4ppm ammonia in 10-12 hours. The problem is I really need some help with determining if my nitrite has spiked because that means I should be reducing the ammonia to 2ppm. I don't want to unnecessarily prolong the nitrite phase by continually adding too much ammonia.

Edit: I just thought, would it be a good idea to test for nitrates? Maybe that would help me determine something more about the nitrite?

 

[Deleted member 55926]

OK, measured again (AM) and the nitrite has now gone to 5+ ppm.

 

[OldMan47]

It always comes in fast like that when it starts processing. Now is the time to start cutting back on the amount of ammonia you add. With the multiplication you get from ammonia ppm to nitrite ppm, it is all you need to keep things moving, and then some.

 

[Deleted member 55926]

Day 11

Ammonia: 0 (dosed up to 2.5ppm - it's the smallest measurement I have)
Nitrite: 5
Nitrate: 20

I am getting a bit lost in the speed of the ammonia processing. It seems 4ppm can easily be processed in under 12 hours, so how often do I dose 2ppm now? Every 24 hours or every 12?

 

[fatheadminnow]

You still/always dose the ammonia at the 24 hour mark.

-FHM

 

[Deleted member 55926]

Day 12

Ammonia: 0
Nitrite: 0
Nitrate: 20

Well, um... my nitrite is 0 today. Bit confused. Does that mean it's done? I wasn't really expecting it to be 0 so quickly.

So what do I do now? See if 4ppm ammonia turns to 0 ammonia, 0 nitrite in 12 hours, for a week? Or do I test just with 2ppm ammonia every day?