Gibboblack Gibboblack
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  • Posted on: 28/3 11:56
Fishless cycle, ammonia vs nitrite #1
Hi All,

First things first. I am new to tropical freshwater fish keeping. It is something that has interested me all my life, and rather than buying a nice sports car for my midlife crisis I've decided caring for fish is a much better pursuit.

I've done a lot of up front reading. This forum has been a very useful resource, thank you :)

I am just looking for advice to help me try and expand my understanding of the nitrogen cycle. There seems to be a lot of conflicting information, and a lot of the instructional information on fishless cycling doesn't really deal with or warn you about what can or might not happen.

To provide a bit of background...

On day1 I set up the tank and left it for 48 hours to warm up and declorinate.
On day3 I added Dr Tims one and only, and dosed the tank with ammonia upto 2ppm.
In the coming days I tested, and re dosed ammonia as instructed
By day11 ammonia was cycling within 24 hours, and nitrite was high.
On reflection nitrite had sky rocketed and me being new to this, I was not reading the chart correctly. I have very quickly learned that I cannot discern the colour above 1ppm. The chart is useless to me above this value. A couple of days passed and...
On day13 I realised perhaps my interpretation of the colours was incorrect. To remedy the situation I made a series of significant but incremental water changes and finally got my nitrite down to 2ppm. Ive taken to measuring fractions of tank water, I.e. A 1/4 tank water to 3/4 tap water as it gives me a more obvious result which I can scale up. My nitrite was in excess of 20ppm.
For the next 2 days I monitored the tank, however nitrite was still going up, even though I hadn't fed the tank since day 11.
On day15 the nitrite was above 5ppm, so I did another water change. Bringing it back to 0.5ppm
On day16 the tank seemed stable 0.5ppm nitrite, 0ppm ammonia. Ph has been stable at 7.4 throughout. Being aware that I hadn't fed it for a while I added 0.5ppm ammonia.
On day17 ammonia was zero and nitrite was between 1 and 2ppm. I dosed 0.5ppm ammonia again.
On day18 ammonia was zero and nitrite bordering on 5ppm. I didnt add any more ammonia
On day19 nitrite is in excess of 5ppm and I'm looking at another water change.

By the way I have no desire to rush the process, my queries are more for understanding, an capturing potential problems. If what is happening above, everybody experiences, then I am more than happy. Just from the myriad of books and Internet articles I've read this sort of thing is just never mentioned.

So to the questions...

1. I had naively believed that 1ppm ammonia would result in 1ppm nitrite, but this doesn't seem to be the case. In fact even when the tank is registering 0ppm ammonia nitrite keeps on going. Is this expected, and does anyone have an idea what 1ppm ammonia equates to in nitrite?

2. Are there other tests I should do? I have tested nitrate, and in the time of the nitrite spike nitrate looked to be at 40ppm. However, I have read high nitrite can cause errors in the nitrate test. More recently nitrate doesn't seem to be on the move, and if it is it is in small amounts.

3. In the interest of getting the tank ready and settled, I did add plants at about day 13/14. Could this cause issues?

4. It would seem to me that Dr Tims one and only has great ammonia oxidising bacteria, but the nitrite bacteria is lacking. I understand it takes longer for nitrite oxidising bacteria to get going, but I thought the additive would be a bit more balanced. The literature and accompanying videos are certainly lacking in alerting users to such issues. Has anyone had similar experiences?

5. Lastly any other pearls of wisdom will be greatfully received, and I have no doubt responses will lead to more questions.

Many thanks in advance.
Fishlady Fishlady
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  • Posted on: 29/3 9:56
Re: Fishless cycle, ammonia vs nitrite #2
Hi

If nitrate isn't rising your nitrite isn't being processed yet. Give it time and it will happen - towards the end of the cycle the nitrite level will suddenly drop back to a readable level and then you'll be a matter of days away from completion.

I can't comment on the bottled bacteria as I have never used any of those products.

Using the molecular weights of the three stages of the cycle 1ppm of ammonia converts to 2.7 ppm nitrite and then 3.6 ppm nitrate so at the end of the cycle nitrate will be very high.

One thing to check on if your cycle is stalling is the kH level in the water. kH is used by the beneficial bacteria to process ammonia into nitrite and nitrite into nitrate so its level drops in a cycling tank. If it falls to low, the cycle can stall as the bacteria are unable to continue processing. This can happen particularly in areas with naturally very soft water which has little kH to begin with. You can address this by raising the kH with bicarbonate of soda - one teaspoon per 50 litres of water raises kH by 4 degrees.
Gibboblack Gibboblack
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  • Posted on: 29/3 16:31
Re: Fishless cycle, ammonia vs nitrite #3
Thanks Fishlady.

I’m happy to wait. I was just surprised at what happened. Most of the articles and literature on the subject show a progressive build of nitrite, where as I experience a huge spike. The graph looks more like the Himalayas. I had read that the process could stall at levels over 5ppm, so I’ve been trying to keep it under that.

The nitrite calc is really good, thanks. I had guessed at about 3 but that’s much more scientific :)

I just did a KH test with some API strips I had. I use the master test kit for usual testing. It is measuring at 40 ppm. Would this be considered low?
Fishlady Fishlady
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  • Posted on: 29/3 16:45
Re: Fishless cycle, ammonia vs nitrite #4
40ppm is fine for kH. If it drops below 18ppm then it's worth addressing either by a water change or by adding bicarb.