Unusual Test Results

[Toby86]

I've been trying to cycle my tank ready for getting some guppies.
I'm using the NT Labs multi test kit.
And tetra safe start.
I've also been enlisting the help of chatgpt to interpret the results.
For close to a week it seemed like the cycling process was going well. Never saw any sign of ammonia. Nitrites were increasing. Nitrates also.
This morning I saw the first signs of nitrites going down and nitrates were still high. I tested again this evening, however and there seems to be no trace of ammonia, nitrites or nitrates.
I did multiple tests and used test tubes from a previous kit. All showing the same result.
I'm a little confused as I though nitrates were supposed to stick around a while after nitrites are gone.
While I did do a water change yesterday I've seen test results saying nitrates and nitrites were high after doing so. It was about a 40% change.
I have 2 questions.
1) the instructions on the kit imply that only reagent bottle 1 of the nitrate test is supposed to be shaken prior to testing. That's what I'd been doing though I shook both this evening as chatgpt told me to. Still 0ppm
2) Is it possible that my tank is cycled and is there a simple way to confirm before buying my fish?

 

[Uberhoust]

1) I don't use NT Labs but the API version only one bottle needs to be vigorously shaken, but I shake both bottles myself. I have proven to myself that if you don't shake them correctly you will get poor results with the amount of nitrate showing less than what's in the water. (confirmed by using a reference solution). I also had a Fluval test for Nitrate never worked no matter how much I shook the reagents.
2) Unlikely. It is the Ammonia and Nitrite that are the most toxic to the fish. If these are not down to zero your tank is not cycled. I would watch for cross contamination if you are not finding the results you expect.

Finally using a fishless cycle usually takes more time than a week. I don't use a fishless cycle but depend on plants mostly to keep the ammonia down but others in the group mention up to 6 weeks.

 

[MaloK]

I would think you tested at the perfect time to have no nitrite reading... But nitrate are still not apparent atm.

Continue on that trajectory, future tests should confirm my "theory"

This happens every time, you closely "follow' any fishless cycle in fact.