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Re: pH hogwash?

Sorry I didn't edit this more, but I feel it's all relevant.

On Sat, 16 Sep 2000 Wright Huntley wrote:
> Hi folks,
> Recent threads, mostly on CO2 (do we even have any others?) have shown some
> attitudes toward pH that are, IMHO, quite unwarranted. I intend to make a
> few blanket statements, based on my experience, that I'm prepared to defend.
> Unfortunately, many books and LFS clerks have wildly *different* opinions,
> so it behooves us to seek the truth, wherever we can find it. That said,
> here goes:
> 1) Fish are remarkably insensitive to pH alone between about 4 and 10, and
> they don't react to it unless some secondary factor is present, that
> altering the pH changes -- like converting ammonium to ammonia. [pH below 3
> can maybe kill some fish. I accidentally did it to some baby Cories, once.
> :-(]
> 2) Plants may have slightly higher sensitivity to pH, tds, hardness, etc.,
> but the boundaries are probably wider than we usually hear about here.
> 3) There simply is no such thing as "pH shock." The fish can't feel or taste
> it, and I routinely subject delicate fish to abrupt changes of 2 or more
> points. In the Scheel _Atlas of Killifishes of The Old World_  he claims
> sudden swings of over 3 points have no effect. An unfortunate connection
> between alkalinity, tds (osmotic pressure) and pH started the myths, and
> many authors have ignorantly propagated them to this day.
> [Don't subject your fish to sudden large changes in dissolved solids (tds)
> for that *can* kill them for sure. They need time to adjust their osmotic
> pressure regulators.]
> 4 ) pH is a useful thing to measure, along with alkalinity (unfortunately
> confused with hardness by calling it "carbonate hardness") primarily to use
> the CO2 concentration equations or charts to set the CO2 level for proper
> plant nutrition.
> [Trying to otherwise adjust the pH chemically, to some false ideal, just
> creates a chemical soup and *more* stress on the fish, and even more lush
> algae, under most circumstances.]
> Keeping the pH from going low in the presence of nitrites and heavy metals,
> or high if a lot of ammonia is present, is a prudent thing to do to keep
> from simply poisoning your fish with these pH-related toxins. Good
> water-change practices and heavy planting virtually eliminates these things
> as considerations.
> [I learned the hard way to keep lead plant anchors out of low-pH, salty
> tanks.]
> Neither fish nor plants really like tds shock, for the cells have to adjust
> to maintain proper concentrations of various salts in the internal fluids. I
> am observing that I kill less "wanted" organisms by paying attention to tds
> change, than I ever did when I thought pH was some kind of magical thing.
> YMMV, but I'll still put up the old flame shield, just out of habit. (^_^)
> Wright

First off, I'd like to say that I completely agree with you.  I am also
somewhat shocked that nobody challenged your opinion on pH sensitivity
concerning fish.

I have expressed my opinions on other boards about pH shock being a
myth, and was flamed to the point where I just gave up.  

Two of my tanks are co2 injected with a pH of 6.4-6.6, while the other
tanks run around 7.4-7.6.  I am constantly moving fish from one tank to
another, and have never seen any symptoms even close to pH shock.  In
fact, I've never had a problem at all.

I am curious about one of your statements.  You stated that a low pH in
the presence of nitrites is bad, can you elaborate on this?

Bob Ashcraft
Pittsburgh, PA