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Re: The "best" way to measure calcium and other minerals
>From: Steve Pushak <teban at powersonic_bc.ca>
>Subject: The "best" way to measure calcium and other minerals
>
> At the moment you will find that most books and a lot of websites quote
> units of degrees of general hardness (GH) when referring to the
> appropriate measurements of mineral content in aquarium water for
> plants. For SHAME!!!
Bullstuff! You have been spouting off on this topic yet seem to have very
little actual information on which to base your spouting. One has to wonder
if you even own a test kit!
> While GH has some meaning for people washing clothes and steam engine
> operators, it has little to do with a meaningful measurement of
> minerals. The units of GH are entirely contrived and you will always
> have to apply some conversion to mg/L or molar concentration in order to
> calculate the appropriate concentrations of minerals.
Well, in the grand scheme of things, are not ALL units of measurement somewhat
contrived? Some people swear by the Metric system, some swear by the English
system but we all manage to get by quite nicely, don't we? Apparently, you
are unable to manage a rough conversion of "20 x dGH = ppm"; this is your
problem and not one that needs to be solved by the aqautic gardening
community.
And in all truth, the "units of GH" are not specifically "German degrees";
that is just what the well respected German firm TetraWerke chose to use for
their test kits. And in all fairness, telling someone that "5 dGH as measured
with the Tetra kit is the norm for community tanks" may be more meaningful and
less angst producing than suggesting that the proper ratio is 83 mg/l of Ca
and 17 mg/l of Mg, derived from specific quantities of hard to find chemicals
as measured on a laboratory analytical scale. For all intents and purposes, as
pointed out recently, there is very little difference to our plants and fish
of calcium levels between 80 mg/l or 90 mg/l (or whatever your species may
require), so why go to all the fuss and bother of making a more accurate
measurement? The tried and true and cheap Tetra kit is completely capable of
producing useful measurements, whether they are in dGH or whatever you want to
convert to.
Why are you in such a lather over this?
> The problem in the aquarium industry is that Joe Q Public, the consumer
> is relatively ignorant of what it is that he should be shopping for when
> he looks for products and test kits. Since the literature refers to GH
> and KH and he only finds test kits calibrated in these arcane unit, he
> continues to BUY those test kits.
If you would take a few minutes and browse some aquarium equipment catalogs,
you might note that, in fact, most test kits offered by the vilified aquarium
industry actually return mg/l or PPM. Tetra, being a German company, is
atuned to the needs of the German aquarist, most of whom do not seem to have
this irrational fear of unit conversion and are quite content knowing that the
5 dGH in their system is adequate.
> So if the great
> unwashed masses (pun intended), thinks that they need test kits which
> are suitable for doing laundry, then that's what the industry is going
> to provide them with.
I wonder if you would stop referring to laundry soap? I imagine George S
regrets by now that he ever dredged up that historical information. It seems
to have sent you over the edge.
> What can WE do about it? I'm a pragmatist ...
If you were, this entire topic would never have seen the light of day.
> 1) We can talk about it and try to agree what are the most appropriate
> and USEFUL measures for mineral content in water.
Having read the archives, FAQs and various websites, it is clear this is NOT
needed, at least outside of the great state of Vancouver.
> 2) We can lobby the aquarium industry to provide us with USEFUL test
> kits and products. By the way, I strongly suspect that all of the big
> aquarium product companies DO have folks who read the APD just to keep
> an ear to the ground.
And since they DO offer USEFUL test kits and products, they are probably
wondering if you are trapped in a wormhole somewhere in a different dimension.
> 3) We can hope that the people who WRITE aquarium literature and
> websites read the APD and agree that its time for a change and we stop
> using units for SOAP to measure minerals in aquariums.
You are once again be confused about units of measure.
> I know on my website I use measures like cups, teaspoons and GH for
> specifying amounts of chemicals. Mea culpa. I plead guilty. My excuse is
> that I'm only pandering to the whims of the public who only have access
> to such measures and tools. (gosh, I feel so CHEAP and TAWDRY!)
Unlike yourself, who has full access to laboratory grade analytical
instruments, chemical and procedures? Gee, you're a prince.
> What are the chances of having an impact?
I imagine one would need to raise a valid concern before one could hope to
have an impact.
> Another point while I'm on my SOAP box; those of you who are using the
> rule of thumb that 1 tsp of CaCO3 raises the GH of 10 gallons of water
> by 2 degrees GH should be aware that this method has an error factor of
> 2 or 3.
I believe most responsible authors always note that the actual GH (or
whatever) should be verified with a test kit after one uses a rule of thumb.
Forrest King
Checking Mr. Booth's WebPage for things I missed the first time
http://www.cco.caltech.edu/~aquaria/AquaticConcepts/