Nitrite levels misreading?

[Madisonkeug]

Hi all, not sure if this is an emergency or not since I don’t actually think my fish are in danger... I’ve been testing my water with the API freshwater master kit (the liquid one) and yesterday I did my second water change of the week at 30-40% somewhere between there and first thing this morning I checked my nitrite levels and it went BRIGHT PURPLE. like I’ve never seen it go so so purple before so I panicked and did a 75% water change and then retested it and it’s still so so purple !? How can this be? I do but weekly water changes on this it’s my 29 Gal tank all it has is a couple dwarf gourami, six Corys and three (possibly four?) kuhli loaches.... I had a pretty fast die off from my Amazon frog bit.... could that be related?
Planning on waiting another 30 minutes and doing a second test as I did my secondary test like instantly after my water change....

Please let me know if you have any ideas/theory’s and if I should be worried or what action you recommend

Thanks all!!

 

[Aquarist2020]

How old is your test kit it might just might be that your test kit expired.

 

[Madisonkeug]

How old is your test kit it might just might be that your test kit expired.

I just bought it from a chain store about a month ago... says ten expiration date is 01/2026

 

[Aquarist2020]

I just bought it from a chain store about a month ago... says ten expiration date is 01/2026

strange, I have heard about these test kits going crazy but I dont know if thats it

 

[Essjay]

Check it by testing tap water.

Could the test tube have been contaminated from the previous test?

 

[Madisonkeug]

Check it by testing tap water.

Could the test tube have been contaminated from the previous test?

Possibly although I usually wash it out pretty thoroughly... I tested against my tap water and it shows 0 so I am once again testing against the tank water and hopefully it shows lower or I may need to set up a hospital tank until I get to the bottom of this

 

[Madisonkeug]

Possibly although I usually wash it out pretty thoroughly... I tested against my tap water and it shows 0 so I am once again testing against the tank water and hopefully it shows lower or I may need to set up a hospital tank until I get to the bottom of this

I have retested the tank and again the test tube has gone PUPLE after yet another 50% water change. I’ve decided to evacuate the kuhli loaches (if I can find them) into my shrimp and tetra tank for now and will put the corys and my Gouramis into my hospital tank(pretty small but will do for now as it’s better than nitrite poisoning) I just need to know what is causing this! I have a heavily planted 29Gal tank set it up about 2 months ago has been fully cycled for this amount of time it has hornwort, Amazon frogbit on surface which has started to melt though, Amazon swords, Aneubius, bacopa, Ludwigia Rubin, and some grasses and a red leaved plant all of which have been doing fairly well (although snacked on by my fish). My substrate is a mixture of fluval stratum, Aqueon shrimp & plant, some rounder black decorative gravel to create spaces for roots, and crushed coral.... what could be causing this anyone have any idea?