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Staw and Dave's Iron Shootout
Thanks to Chris Coleman for the info on barley straw and algae. I found
the referenced article http://www.execpc.com/~aqsys/barley.html
<http://www.execpc.com/~aqsys/barley.html> interesting and wondered if
any of our botanist friends (dr. dave are you still out there?) think
the argument is plausible. And does anyone see a danger to our tropical
fish in the chemistry mentioned? I recall the repeated cautions about
hydrogen peroxide that we have heard here on the APD. I ordered a pound
of barley straw this morning. At the recommended pond dosage of 10
g/sq. meter of surface area per 6 months, I should have lots to share,
if the initial experiment is promising.
Dave Gomberg wrote: "Well, Steve Dixon and I had the great iron test
kit shootout at my house yesterday and the entrants were Hach, LaMotte,
Sera and Schoeler's.
I was an advocate going in and I am an advocate coming out. I think
the Sera is by far the best deal. It is sometimes not easy to learn to
read it (if you want to tell the difference between 25 and 50 ppb (which
the other tests cannot even try to detect), otherwise for higher levels
it is easy to use). And it is reasonably priced ($12 for hundreds of
tests). Contact me offline for more info."
I hate like heck to disagree with Dave, but since I do, I will. We
didn't test any of the reference solutions Dave made up with the
non-Sera test kits and I don't recall any tests with Karl Schoeler's
kit--so we just don't know what the results might have been. In any
event the reference solutions did not include chelated iron so we also
wouldn't have had any info on that score either. I tried and tried to
see some color in Dave's 25 and 50 ppb solutions but just couldn't make
it out. To be fair I have very slight color blindness in the blue/green
range, so perhaps I just couldn't see the lightest shades of pink that
Dave saw.
My experience with the Sera iron kit is that it couldn't read low levels
of chelated iron; that when one does get a reading, the reading always
seems to be 0.1 ppm; and that at higher levels than 0.1 ppm, which for
me have often brought on algae problems, the Sera kit still reads either
0.0 or 0.1 ppm. I found it virtually useless and nearly always
misleading. It is the only test kit that I ever just pitched into the
garbage can and I remain glad of it.
I would be interested in a real iron test kit shootout using both
chelated and non-chelated reference solutions. But until the Sera kit
proves itself, buy Hach or LaMotte.
Regards, Steve Dixon in San Francisco