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Re: [Killietalk] Cloromine (sic)

It's the other way around, Edd. St. Louis is almost a worst case scenario! All the more reason to be startled at Charles's success.

There's an equilibrium ratio of harmless ammonium ion (NH4+) and toxic Ammonia (NH3) that depends on pH (and temp.). High pH converts more to the deadly form and pH below about 7 produces so little we usually can ignore it.

Some typical percentages are (at 20C):

pH NH4+ NH3

7.0 99.5 0.5

8.0 95.3 4.7

9.0 64.2 35.8

9.5 38.9 62.1

At 15C that last number drops to 57.6, but would also increase a bit at higher temps. The 50% crossover point is between 9.0 and 9.5. Below that pH, more is harmless ammonium ions. Above that, more is as deadly un-ionized ammonia.

Increasing dissolved oxygen also greatly reduces ammonia toxicity.

Don't forget that we see so much ammonium, and so little ammonia, under normal circumstances, that we tend to forget that ammonia is potentially harmful at way down around a few parts per billion. Even the 1.5% at a pH of 7.5 and a temp. of 20C is quite significant, based on the studies cited in Spotte (_Fish and Invertebrate Culture_), if total ammonium/ammonia is around 1 ppm ( a common value). They calculated levels of 6-8 ppb caused significant gill damage and permanent stunting in baby salmonids. YMMV and Charles's obviously does. :-)

Folks have said they have been getting away with it. Well, I, personally, did not, which may explain my tendency to go on too much about it.

We had a unfortunate backup of San Jose water into our Santa Clara well pipes. When I saw the fish in distress during water change, I started testing and detected chlorine. I immediately popped in some dechlor product and promptly killed some of my fish. Apparently the low-level chloramine (which was totally unexpected) did the fish less harm than the subsequent release of ammonium/ammonia. My normal pH was high and the water quite hard (8 and 450 ppm). IDK if the San Jose water was similar, because I was too horrified to think and measure it. I have a hunch it was RO water that had added CaOH to raise the pH, as well as the chloramine. I only found out it was chloramine, later. All this was years ago and should be measured against my memory (which is still my second-shortest thing).

When you lose a few favorite fish, and are quite sure it was because the hypo acting on chloramine killed them, you can be made a believer very quickly.

Wright


Kray, Edd wrote:

One question on this chloramines controversy. How does the rather
aberrant pH of St Louis water effect this situation ? I recall that the
pH there is close to 9. Doesn't this effectively reduce the toxity of
the ammonia  released by the hypo. Whereas in a situation with more
normal pH (7), the ammonia might be a real problem. So experience unique
to St Louis may not apply to the majority of the rest of the US.



--
Wright Huntley -- 760 872-3995 -- Rt. 001 Box K36, Bishop CA 93514

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