[pct-l] Aquamira info

[Andrew Jones]

You guys were asking for a chemist's opinion. I'm a chemist at a brewery,
where we use chlorine dioxide as a surface sanitizer, so here we go.

First off, the shelf life of Aquamira. Sodium Chlorite solution (solution A,
I believe) is very stable as long as it's kept cool and away from light. I'm
not technically advising you to use Aquamira past its expiration date to
absolve my liability, but I can't think of a reason for it to go bad as long
as it's kept cool and relatively dark (I think it's in a solid white plastic
bottle...?).

After mixing the solutions, the pH should drop to between 4-5, and the
chlorite will start to convert to chlorine dioxide. It is this molecule that
has sanitizing activity, NOT free oxygen. *This is a gas in solution*, so
the life of the activated solution is somewhat short (a matter of a couple
hours, depending on concentration). For anybody that cares, what's actually
happening is an equalibrium is established between the chlorite and chlorine
dioxide. As the chlorine dioxide leaves the water (remember, it's a gas),
more of the chlorite is converted until it's gone. This gives the solution
moderate stability, but as I said, only for a few hours, after which the
concentration of both chemicals drops to a non-active level. THE BEST OPTION
IS TO USE IT IMMEDIATELY AFTER ACTIVATION! ONLY THEN CAN YOU BE POSITIVE THE
SOLUTION HAS THE CONCENTRATION INTENDED FOR USE BY THE MANUFACTURER.

As for homemade kits, if you're a chemist and you know what you're doing,
feel free to go ahead, at your own risk. I will not give advice on how to do
this for liability's sake, but keep in mind the activation solution must be
between 4-5 pH, and I would only trust high quality pH strips to check this
unless I was VERY confident in my drop size measurement method. These run
$40 per 100, so you've just increased your cost 40 cents per treatment.
Hopefully I've talked you all out of this....

And with all treatment options, remember, none are foolproof. Measuring
treatments by drop size is inaccurate, iodine tablets decompose over time,
no chemical treatment can really penetrate solid particles unless given
hours or days to do so, UV-C lights have the same problem with particles,
and filters honestly are only as good as their o-rings or membrane
construction (also Cryptosporidium, for example, is small enough to
penetrate some ceramic membranes). The ONLY 100% reliable treatment option
is boiling for at least 3 minutes! Not gonna happen! So what cold treatments
do is REDUCE the bacteria/viruses to a level that can be withstood by an
average human immune system. If you have a compromised immune system, I
would recommend using more than one treatment method every time. Otherwise,
just use the treatment of your choice, and quit your worrying, you're going
to make yourself sick!!

Andy