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

[Wright Huntley <whuntley at verizon_net>]

Scott Douglass wrote:
> Wright,
>
> It is a while since we argued ;)
>   
Long time, no disagree! :-)
> I still have to disagree with you - a little, on the pH thing.
>   
Ask me why I'm not surprised.
> In most cases freshwater fish are quite adaptable with pH, but their
> physiology is such that different species are adapted to different pH
> ranges.
>   
I don't think we actually disagree much on that.
> Often we might not notice this directly, but it does place increased stress
> on the fish, in particular the respiratory system and the kidneys. Also the
> blood of fish is quite complex compared to other animals and is quite
> dependent on pH, Root effect etc. 
>
> Although agreed most freshwater fish are quite tolerant of variations of pH,
> but fish in general have to spend a fair amount of energy keeping their
> blood chemistry correct.
>   
Amen, brother. You are preaching to the choir, on that. My point was 
that external factors depending on pH are most often the important ones, 
but I do agree that there is a "best pH" range for some species. Low for 
wild Bettas, because they like/tolerate the kinds of bacteria that grow 
there, for example.
> For fish from very particular environments I would be cautious of ignoring
> pH too much as their Kidneys in particular and respiratory system to a
> degree would be placed under increased stress.
I find few killies, other than maybe brackish/salt-water species, that 
seem to give a damn. In many cases, the osmotic pressure of the 
dissolved solids is a far bigger factor than the pH. I use my tds meters 
at least 10 times as often as my pH meters. Soft or hard water are far 
more important to most species.

OTOH, I think your concerns are most valid when it comes to eggs. I 
suspect they are less adaptable than their parents to alien conditions, 
and pH could well be one of those factors (but probably less important 
than other pH-dependent chemistry parameters).
>  
>
> The renal system is used to excrete excess H+ etc. That is also one reason
> why marine fish are very specific in terms of pH as they do not have the
> excretory capacity of freshwater fish. Other inorganic salts are used such
> as Phosphates, Carbonates and other -ates and similar in these excretory
> functions. Since solubility is highly dependent on pH, lots of very weird
> things can happen when you have unusual situations like low pH and high
> Hardness and vice versa. I remember vaguely reading something about crystal
> formation due to precipitation on gill membranes in such circumstances.  
>   
This doesn't negate the fact that most published hobby info on pH is 
bunk, and most fish stores believe absolutely anything they read in 
Baensch, et al. They love to use it to sell hugely over-priced test kits 
that their customers really don't need. They mostly don't even stock a 
decent chlorine test, which is also very cheap at the local pool and spa 
vendor. 90% of the "infertility" cases I have observed have been due to 
low levels of chlorine/chloramine, that the fishkeeper insisted were not 
in his (untested) water.
> Another side effect of unfamiliar pH for a fish would be increased
> metabolism.
>   
Possible, but it isn't something I have ever observed directly.
> Still in general I agree a lot of freshwater fish could not care less, but
> for those fish from particular environments, or when you start getting into
> extremes then I am sure pH becomes quite important.
>   
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. [The high pH changes some of the 
harmless ammonium ions to dissolved ammonia, 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.]

I don't think we basically disagree. My main point was to understand 
what is happening at different pH and not blindly accept a few 
chemically-uneducated Atlas authors who have all copied from each other. 
That can lead to attitudes like Mach's that he can't raise killies 
because he has perfect killy water but doesn't know how to deal with the 
regulatory problems (that always cause unintended consequences). A 
little proper carbon filtering can make all his problems vanish, but it 
will do nothing to the pH. OK?

Let's find something upon which we can really disagree. Politics? Aussie 
"English?" We are playing nasty tag, and you are it! ;-)

Cheers,

Wright

-- 
760 872-3995 760 937-2276 (Cell)
RR 001 Box K36
[85 Schober Ln. Sp 36]
Bishop, CA 93514

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