Fishless tank cycle question

[iapereira]

Hi all,

I did a fishless 2-3 weeks cycle on my new aquarium, yesterday I tested the water for ammonia, nitrite and nitrate. Ammonia was 0ppm, nitrite was 2ppm, and nitrate was 80ppm. Everything seems fine with the aquarium and I was waiting for the nitrite to be 0ppm to do a 25% WC.
However, this morning I tested again (twice) and all parameters were reading 0ppm. Is that possible to happen? What should I do in this case?

 

[Mr. Mojo Rising]

IMO it seems to be a testing error, either yesterday or today, nothing can make it change that fast. Which test kit are you using?

 

[iapereira]

IMO it seems to be a testing error, either yesterday or today, nothing can make it change that fast. Which test kit are you using?

Im using API the testing, my understanding is that it is not the best.
My fish is still in QT, what should I do to keep the bacteria alive for around 1.5 week?

 

[Mr. Mojo Rising]

Im using API the testing, my understanding is that it is not the best.
My fish is still in QT, what should I do to keep the bacteria alive for around 1.5 week?

The correct way to confirm a cycle is to add ammonia until it gets to 2 ppm, if the tank is cycled then it should drop to zero overnight, and you should nitrate around 15-20, that is a cycled tank.

API is not the best, but definitely good enough to get through a cycle, so I could only conclude that tested incorrectly either yesterday or today, its a pretty big difference between 0 and 80 lol. I would suggest to double check the instructions, perhaps even search out a youtube video showing how to do the test.

A fishless cycle is about 3 weeks, so you should be just about done.

Can I ask how exactly you started the cycle? what bacteria and ammonia?

 

[iapereira]

The correct way to confirm a cycle is to add ammonia until it gets to 2 ppm, if the tank is cycled then it should drop to zero overnight, and you should nitrate around 15-20, that is a cycled tank.

API is not the best, but definitely good enough to get through a cycle, so I could only conclude that tested incorrectly either yesterday or today, its a pretty big difference between 0 and 80 lol. I would suggest to double check the instructions, perhaps even search out a youtube video showing how to do the test.

A fishless cycle is about 3 weeks, so you should be just about done.

Can I ask how exactly you started the cycle? what bacteria and ammonia?

Yes, of course. I initially added microbacter start xlm for the bacteria and Fritz Zyme Fishless Food for the ammonia. I have a 50gal tank, so I brought the ammonia up to 2ppm and was tracking them for the past 2.5 weeks.

I just added 2ppm to the tank and will check it tomorrow! Feels like Im close to have the tank cycled like you said! Thank you for the help!

 

[iapereira]

Hey, so a little update, as mentioned I added the 2ppm last week. Everything went fine, ammonia dropped to nearly zero (as far as I can tell with API), nitrite increased along with nitrate; a couple days later nitrite went to zero and nitrate was the at pretty high levels on sunday night.
The strange situation starts now, I skept testing yesterday and tested this morning, and for my surprise everything was zero again.

My question is: where is the nitrate going? This is the second time this happens lol
Is there any bacteria that might be well developed and is consuming the nitrate? Might be a dumb question, but I need to understand where it is going.

Also, do I need to do a water change if Im reading zeros across the board before adding the fish?

 

[Randy Holmes-Farley Verified Community Expert]

There likely was not much nitrate, just the small amount the ammonia produced that is readily taken up by growing bacteria and algae. A little nitrite reads falsely as a lot of nitrate, but is not real nitrate.

No reason to change water.