Brand New Tank, Bacterial Bloom?

[eaglesaquarium]

I've done it both ways - with the WC and without.  In my experience, doing the water change to remove the nitrites actually speeds up the process, because the AOBs are going to produce the nitrite quickly after the water change, and so the NOBs will have something to work with, BUT they won't have to go through the EXCESS nitrite that has built up while they are trying to get their colony underway. 
 
 
I did no water change with my original fishless cycle, and I've done a water change with a "seeded" fishless cycle on a large tank.  In the large tank, the AOBs were plowing through 3ppm ammonia rapidly, but the NOBs just weren't able to keep up and quickly I found myself off the chart.  I also had nitrates starting to climb (showing that the NOBs were working, just not at a high enough pace to keep up with the AOBs).  I did a full water change to zero out the nitrites and nitrates and give the NOBs a fighting chance of catching up to the production of the AOBs.  This worked perfectly for me, and two days later the tank was completely cycling through 3ppm ammonia daily with 0ppm ammonia and nitrite after 24 hours...  Then the issue came of when it would reach zero in 12 hours.  I never did find out when it reached zero after only 12 hours.  This tank is at work, and I wasn't going to go out of my way to test it after 12 hours.  No problems.

 

[fatheadminnow]

This is cool.  There is more than one way to fishless cycle a tank.  I guess if both work just as good, by all means do the one you feel is better. 

 

[TheRandomHero]

Well I will leave it tonight, I took a photo of the test tube against a white monitor background, and I will do the same again tomorrow afternoon, if there is no change at all I think I will do another, larger WC, to try and help the NOB's get to work a bit better. Trial and error from hereon in
 
I just worry that it's going to do the same again, because I keep adding ammonia to feed the AOB's.... won't this result in a massive flux of Nitrite again? Or would a 90% WC be better because then the little Nitrite left will help colonise the NOB's while the AOB's get to work on the ammonia i would dose after the change?....

 

[fatheadminnow]

Well I will leave it tonight, I took a photo of the test tube against a white monitor background, and I will do the same again tomorrow afternoon, if there is no change at all I think I will do another, larger WC, to try and help the NOB's get to work a bit better. Trial and error from hereon in

 
I just worry that it's going to do the same again, because I keep adding ammonia to feed the AOB's.... won't this result in a massive flux of Nitrite again? Or would a 90% WC be better because then the little Nitrite left will help colonise the NOB's while the AOB's get to work on the ammonia i would dose after the change?....

 
That is correct.  If you doa  90% water change the NOB's will still work on the nitrite that is there after the water change.  Then, yes, dose back up to 5 ppm of ammonia.  Let it sit for now as you said and see what it looks like tomorrow.

 

[TheRandomHero]

Well the Nitrites hadn't budged, but as usual the Ammonia was gone. Just gone and done a 90% WC... gonna give it an hour to circulate then I'll do another Nitrite reading

 
 
OK so just done the Nitrite reading, and it's looking about 0.5ppm.... shall i give it 12 hours to boost the NOB's before adding Ammonia again?

 

[fatheadminnow]

I would add some ammonia.  Then check it in 12 hours or so.  

 

[TheRandomHero]

Just put the Ammonia to 5ppm. We'll see how the next 24 hours go I'll take a Nitrites reading before bed and first thing tomorrow so I can gauge its progress easier

 

[TheRandomHero]

OK so 5 hours down and we've gone from 5 Ammonia/ 0.5 Nitrites, to 2 Ammonia/2.5 Nitrites.
 
I'm wondering how to juggle the 'monitoring Nitrites falling' and 'feeding ammonia to keep AOB's alive'..... I don't want to keep adding large amounts of ammonia because I'll just end up with sky high Nitrites again....

 

[fatheadminnow]

I would say to keep doing what you are doing.  I forgot the correct correlations but for like every 1 ppm of ammonia processed it goes to like 2-3 ppm of nitrite.  So you have, theoretically processed about 8-10ppm of nitrite.  So the NOB's are there and they are doing their job.  Keep in eye on them.  When you dose ammonia, do so in 24 hour increments.  Just keep an eye on it.  I am assuming you should see 0 ppm of nitrite within a couple days.  NOB's usually, in my experience, colonize much faster than AOB's. 

 

[TheRandomHero]

Well fingers crossed I'll post tomorrow night with both AM and PM results.

 

[eaglesaquarium]

1ppm ammonia processes to 2.7ppm nitrite, as measured by the API test kit.
 
So, cycling through 3ppm ammonia, means you've generated 8.1ppm nitrite, but only showed a gain of 2.0ppm nitrites, so you are getting a 6ppm nitrite conversion in only 5 hours.
 
 
More than likely, you will find the nitrites are at a very low level when you test 24 hours from the dose time, possibly even 0, but more likely 0.25-1.0.   No sense getting too worked up about it.  One benefit of the big WC is that you reset the buffering ability of your water and rebuilt the carbonate in the water, offering the bacteria the necessary carbon to build their colony and biofilm that they require.  Things are going well.  Remain patient, the end is in sight!

 

[TheRandomHero]

Just did a test, there's still a slight ammonia, like 0.25 but my nitrites is huge again, instantly a deep purple... its been 19 hours since the 5ppm dose of ammonia. I find it weird that after all this time of getting 0 ammonia in a few hours, there's now a little left over...

 

[eaglesaquarium]

That happens sometimes...  Its not unusual.  Remember, that processing the ammonia is not the ONLY thing that the bacteria need to do.  Sometimes they are putting more effort into building their biofilm.  This will allow them to be far more robust and resilient than without it.
 
 
Patience...  I'd drop the ammonia dose for a while though and allow the NOBs to catch up.  3ppm is plenty for the AOBs to survive on while the NOBs catch up.

 

[TheRandomHero]

That's good to know I'll redose tonight to 3ppm and keep an eye on the nitrites for the next couple of days

 

[TheRandomHero]

Another day, another deep purple result