Re: [Killietalk] pH (was Re: copper leaching from new plumbing)

[Kenneth Combs <ken_combs at sbcglobal.net>]

Interesting thread on pH....funny, for all the meters & test kit's I've bought, can't recall too many times I've actually bothered adjusting the pH anyway...
Still....
Wright wrote:
>Again, I suggest it is the impact of pH change on other chemistry that 
>is usually most important, and understanding why a shipped bag of 
>ammonium-loaded fish dies when exposed to local high-pH tap water 
>(ammonia poisoning) is more important than thinking the fish are subject 
>to an unreal thing like pH shock. 

nice: esp the pH/water Chemistry interaction thing, pretty much why us reef fanactics monitor pH as a "indicator" variable...but gotta wonder how many discus breeders would test the pH shock theory by subjecting a tankfull of 7" breeders to a 6pt pH drop in a matter of hours (assuming the discus are in the "usual" zero nitrate pristine water many keep them in)

...I'm also reminded of that "Acid rain" panic of the 70's 80's (that went away once the "neocons" invaded DC)...there was once a lot of diatribe over "dead" lakes and pictures of floating brook trout in "acid pools"..anyhow, they way the media sold us simpleton joe public types was a direct cause & effect from the acid fall out as opposed to some complex "chemical interaction" from ammonia or whatever...and I realize we are talking killies not trout, but one guesses pH must matter on some level or did all those US Gov biologist frame the entire matter in a way us non PhD types can understand? ...

Wright went on to explain (trunacated):
>... which is deadly at very low 
>levels. Their equilibrium is pH and temperature dependent. This or 
>osmotic-pressure shock are the source of about 90% of the pH mythology 
>(and temperature-shock mythology). Scheel reports sudden changes of 
>three points in pH with no observed distress, and I have routinely 
>ignored two or more points difference, as long as no ammonium or nitrite 
>was present. I still often use drip acclimation for new fish, but mostly 
>to avoid osmosis problems or to give the squirt of Amquel time to 
>neutralize the ammonium.]

Makes one wish the plethora of bad "Aquarium books" would expound on that, esp. as things get tricky when a tank's pH will oftentimes drift downward from biological processes or whatever...but, IME there is definetley a difference when dumping a fish directly from a bag into warm tank water vs. colder water (IMHO there is a distinction when going from warm-to-cold vs. cold-to-warmer, regardless)...there also appears to be a difference if said water originates from a pipe (spicket/tap)...basically I'm wondering if "temperature shock" has been the scapegoat when the real culprit might have been a diff. in disolved gasses or lack thereof...("N2 shock" ain't no myth)

KC
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