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Can there be ammonia and nitrates, but no nitrites? (Free Ammonia?)


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My tank isn't very old.  I'm on my 3rd week of water testing, and did a partial water change last week. 

The last 2 tests I've seen something peculiar :  ammonia is 0.25, nitrite is 0, and nitrate is about 5ppm.

It read the same last week except nitrate seemed closer to 10ppm.

My understanding of the Nitrogen cycle is that ammonia would be consumed and nitrites are formed.  Nitrites are consumed and nitrates are formed.  So I should normally see ammonia and nitrite at 0, and some value of nitrate (assuming no plants). 

If there's a small amount of ammonia, but no nitrite, is it that there wasn't enough bacteria to consume to ammonia, but plenty to consume to nitrite? 


I used API Quick Start before I added the fish. Not sure if that's telling of what's happening.

Or maybe this is normal? 

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Are you using the API master test kit or test strips. I have seen some places say that the test kit can some times show a weak positive ammonia. Another possibility is nitrates in your tap water so might test that as well. Something to think about at least

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API Master Test Kit.  The first week I tested, it was clearly zero, along with nitrites being zero, and nitrates were 5ppm.  So I know it has been 0 before.  But never got lower (or higher) than .25 since.

Just to be on the safe side, I put Prime in until I can do a water change (if necessary).  20210310_140335.jpg.19383c8867868e0ce23a57562404d230.jpg


I will maybe wait until Friday to do another test.  Perhaps it just hasn't been nitrified yet.  

But I'm also learning other things like my baffled output of the filter could decrease aeration of the water which could otherwise help reduce ammonia.  If that's the case, this might be something I have to deal with weekly until it settles.

It's a 10 gallon with about 2inches of gravel substrate.  Only one fish.  


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I've also been reading about "Free Ammonia".   The test kits measure Total Ammonia Nitrogen.   I'm not a chemist so I'm not going to pretend to understand it all - but basically this is two types of ammonia measured together.  The one you should be concerned about is the un-ionized or free ammonia.   

I used this calculator: https://thepetsupplyguy.com/unionized-ammonia-calculator/

According to this, and other calculators that do the same thing, my free ammonia is about .003ppm.  You should start to get concerned when it is .02.  So this is okay...

Obviously, 0 is ideal.  

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Can you have ammonia and nitrates but no nitrites? Yes. The reason is that it's a different bacteria that converts nitrites to nitrates. If that bacteria is better established than the bacteria that converts ammonia to nitrites it can be just sitting there waiting for any nitrites to come along and gulping them down and churning out nitrates as quick as they come. Think of it as an assembly line with three stations. The first station has a very slow worker. Every time you look at that first station he/she is methodically plodding away at their task (in this case converting ammonia to nitrites.) The worker at station two however is blindingly fast and every time you look they're just sitting there twiddling their thumbs waiting for the next batch of nitrites from the first station to get to them. As soon as it arrives they've grabbed it converted it to nitrates and passed it on. They've done their job and are sitting there waiting for more. Meanwhile the nitrates are piling up on workstation three. When you look you see all kinds of ammonia, all kinds of nitrates, but no nitrites. The bacteria converting the nitrites to nitrates are just working really hard, fast and doing a good job. It's pretty easy to have ammonia and nitrates without nitrites if those bacteria are thriving.

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