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Re: Formalin question
Barry Cooper wrote:
> have you actually bought 37% formaldehyde at a drugstore?
I have to admit that my last bottle came from LabPro in Sunnyvale, an
industrial chemical supplier. I have not gotten it, potassium permanganate,
or a lot of other useful stuff from drugstores in years. [The KmNO4 is from
Sears, these days!] The chemical hysteria and trial lawyers seem to have
driven them off the market. No regulations were even needed, for many. I
think I have *seen* it in CA drugstores in recent years, tho. Could easily
> If so, I'd be
> surprised. In many states there are restrictions on buying formalin and on
> how you have to dispose of it. It is allegedly carcinogenic, although as
> someone whose profession uses it by the barrelful, I think that is
How come so many vertebrate paleontologists (and killy taxonomists) grow to
such advanced age, if it is so vicious? [As far as I can tell, "lumpers"
*may* eventually pass on, but "splitters" are seemingly immortal. :^)]
> Anyway, I doubt that many drugstores carry it. Your best bet,
> in my opinion, is to ask your veterinarian. Some of them will have the 37%
> stuff that they dilute 1:10 for fixing tissue for submission to a pathology
> service. Others will have the 10% solution ready made. The latter is fine.
> You just use 10 drops/gal rather than 1. Just be sure which one you are
> using. Personally I feel more comfortable with people using 10% anyway, as
> 37% formaldehyde is dangerous stuff for which you must avoid skin contact,
> breathing vapors, etc.
> The nomenclature is confusing by the way. Formalin, as far as I know, is
> not an old brand name, but the name given to a 37% solution of
> formaldehyde, which is a gas. We then use the term, 10% formalin. That is a
> 1:10 dilution of the strong stuff and is usually buffered with phosphates.
> The latter won't do any harm if you use 10% formalin to kill hydra. You'll
> get rid of most of it anyway when you do the requisite water change.
The phosphates can potentially do a real number on your tanks, if you don't
care for algae. [Depends greatly on your original plant-nutrient balance.]
My experience with the 3.7% stuff (10% Formalin) is that it often isn't very
stable, and is worthless after about six months in the sun on the LFS rack.
It also costs about 100X as much.
"Formalin," BTW, is, I think, a very old trade name, gone generic, very much
like aspirin (acetylsalicylic acid). It isn't either a currently-valid
registered trade name or mark, AFAIK.
Wright Huntley, Fremont CA, USA, 510 494-8679 wright at killi dot net
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