My First Time Fishless Cycling - Doing It Right?

Patience is the word now.

Strictly speaking you should have:
Day 1 - added 3ppm ammonia
Day 2 and day 3 - nothing
Day 4 - tested and got 0.5ppm ammonia and 3ppm nitrite; add 3ppm ammonia
Day 5 - nothing
Day 6 - tested and got 0ppm ammonia and 3ppm nitrite (though you should really have missed 2 days and tested on Day 7)

So far, so good.
But you shouldn't have added any more ammonia yet. You need 2 test days with zero ammonia.  So you should have continued:

Day 7 - nothing
Day 8 - tested and if ammonia had been zero then as well, add 1ppm ammonia.

The problem you are facing is that you added 3ppm ammonia on Day 6 instead of waiting for Day 8's test results. It is likely that your nitrite is too high. The chap who wrote this method intended that it should never give a too-high nitrite because if nitrite gets over 15ppm, it stalls the cycle. And our test kits can't measure that high so we don't know if it is too high; all readings over the highest on the colour chart just show as that level.

The simplest way to get back on track is a water change. Big enough to dilute the nitrite reading to around 2 to 3ppm. Maybe test a sample and see how much you need to dilute that then you know how big the water change needs to be.
Once you have a nitrite reading in the middle of the chart, go to step 9. That is, test every second day and if ammonia is zero and nitrite over 1, add the one third dose. As soon as the every-second-day results are ammonia under 0.25 and nitrite under 1ppm, you will be at stage 10; that is when you add the full 3ppm dose and test in 24 hours.



1ppm ammonia is converted to 2.7ppm nitrite. You added 9ppm ammonia by Day 6 and even allowing for some nitrite to be converted to nitrate, that would have pushed the nitrite level over the 15ppm critical level.

I've come to the conclusion that fishkeeping is more about looking after the bacteria in the water so that they look after the fish for you.

That is very true. If the water is right, the fish more or less look after themselves.


I didn't include the ammonia to nitrite amounts in the method as I didn't want to make it more confusing than necessary. I figured I could always tell someone who was interested separately.
And just for completion, that same 1ppm ammonia, after it has been converted to nitrite and then onwards to nitrate, ends up as 3.6ppm nitrate. This is why nitrate gets quite high during cycling, and the reason for the big water change at the end, before you get fish.

I would play it cautiously. Add a one-third dose now and test after 48 hours. The ammonia eaters won't starve (like it used to be thought).
In 2 days, if the results are zero ammonia and nitrite over 1, add another one-third dose and test again in another 2 days.
But if the results are ammonia less than 0.25 and nitrite less than 1, add the full dose and test after 24 hours.

This way, you'll find out in a couple of days if your nitrite eaters are growing nicely without the risk of making too much nitrite if they aren't.

Well after yesterday's big water change I added a one third dose bringing ammonia up to 1ppm.

I couldn't resist taking measurements again today (day 12) and unsurprisingly my ammonia was at 0ppm.
I was very surprised to read nitrites at 0ppm.  Already?

I did seed from an previously cycled tank so that certainly kickstarted things.

I had forgotten to mention I have been dosing with Interpet Filter Start, every other day.
I don't have particular faith in these kind of products but, as it came free with my setup, I thought I might as well use it. Perhaps it's helped, a little, too ...


On Sue's advice I've now added a full dose to bring ammonia back up to 3ppm and I'll test again tomorrow, hoping for two zeros.

Once I know the cycle is compete, because I haven't yet decided how I'm going to manage RO water and I've yet to plant up, I'll keep the cycle going by adding a one third dose every other day and a full 3ppm dose every two weeks.
Then a big water change the day before the first inhabitants are added, to get rid of the nitrates.

Well done