54G tank appears fully cycled after 14 days? Fish in cycle?

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Lollum96

Black Skirt Tetra
MFK Member
Mar 9, 2023
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Set up a 54g corner aquarium about a month ago. 2 weeks ago I added the first fish, no effort was made to start the cycling process for the prior two weeks of the tank being set up. I just simply didn't get around to adding fish for two weeks.

Anyway 14 days ago 2 x 3" angel fish and a 3" rainbow shark where all added to the 54g corner aquarium to start the fish in cycling process.

First week I didn't check any water parameters.

Day 8 I tested ammonia 0, nitrite 0 and nitrate 0

Day 11 I tested ammonia 0, nitrite 0 and nitrate 5 ppm.

Day 14 I tested ammonia 0, nitrite 0 and nitrate 10ppm

As said I find it very strange and I would have expected the fish in cycle to be just begining. But I'm consistently getting 0 for nitrites and ammonia and I'm now getting steadily rising nitrate levels which should indicate stage 3 of the cycling process?

What do you all think?

When I set the tank up a month ago I used old gravel that I had originally used in an aquarium. I give the gravel a good clean in a sieve through tap water but it still contained loads of snail shells from live plants that I had in the old tank

Could any organic matter that was left behind in the gravel such as maybe some dead snails have kick started the cycle from day 1? Instead of when I added the first fish after 14 days?

Using an APi master test kit for all the testing backed up by an NT labs kit which has gave the exact same results. Consistently 0 for ammonia and nitrite but steadily rising nitrate levels.
 
Anyone got any ideas? Does the presence of nitrate indicate that the tank is actually cycled?
 
That is a bit odd, but yes when you see 0 ammonia and nitrite and rising nitrate it would seem cycled. I wouldn't think anyhting survived on the old substrate, there could have been organic material that continued decaying once introduced to the new system, thus producing ammonia and starting a cycle, but a couple weeks seems unlikely to have finished cycling. Have you tested your source water for nitrates? Perhaps your cycle didn;t even start yet. Did you use any filter media from an established tank?
 
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