Chlorine bleach affect ammonia test?

[Myka]

Anyway, I just poured about a cup of bleach into a 40-gallon quarantine tank. I am now curious if there was ammonia in the tank, and did an API test which shows negative for ammonia. Is the chlorine bleach causing a possibly false negative?

 

[Randy Holmes-Farley]

bleach can react with ammonia. I'm not sure to what extent it happened in your case, but I would not assume there's no ammonia.

If there is substantial bleach remaining, it may also directly mess with the chemistry in an ammonia kit.

 

[Myka]

bleach can react with ammonia. I'm not sure to what extent it happened in your case, but I would not assume there's no ammonia.

If there is substantial bleach remaining, it may also directly mess with the chemistry in an ammonia kit.

Interesting. Ok. If I add dechlor, could I get a true reading then? It's only been about 15 hours.

 

[Randy Holmes-Farley]

Interesting. Ok. If I add dechlor, could I get a true reading then? It's only been about 15 hours.

Not for ammonia that already reacted with the bleach, but perhaps for newly generated ammonia. Why do you want to measure ammonia in that situation?

 

[Myka]

Not for ammonia that already reacted with the bleach, but perhaps for newly generated ammonia. Why do you want to measure ammonia in that situation?

Ok, that wouldn't do me any good then as newly generated ammonia isn't a concern.

It's in a QT. There was an issue with the fish. It seemed like a bacterial problem. I transferred the fish out to a different tank, then dumped bleach in. Once the fish were transferred I had a closer look and they appeared to have signs of ammonia poisoning (clamped fins with a bit of blood streaks, heavy breathing, one had cloudy eyes which was my main alert to ammonia). I had two Ammonia Alert badges in the tank (one 10 months old, one 1 month old), neither said there was ammonia, and there was no good reason for ammonia to appear in this Qt at this time. I've never had an ammonia alert fail me (used them extensively for MO culture). So then I was trying to get a reading from a test kit as a third "opinion", but I had already added the bleach. After I added the bleach, the ammonia alerts both changed color to a mild ammonia reading which is normal IME, so it seems like they are working.

I just wanted to cover my bases. If it wasn't ammonia, then why have they perked up now in a new tank? If it was ammonia, why (the freaking heck) was it there? <-- rhetorical questions

 

[Randy Holmes-Farley]

OK, so it is an after event attempt to determine what might have bothered them?

 

[Myka]

OK, so it is an after event attempt to determine what might have bothered them?

Yes.

Fwiw, the Ammonia Alerts had a small shade of ammonia showing on them immediately after adding the bleach, and then faded back to yellow (no ammonia) within 6 hours which seems to be normal when adding bleach to tanks with no ammonia from previous experiences.