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Re: Call for observations...

Thanks Paul, for your list of symptoms.

As far as toxicity is concerned, EPA has compiled, interpreted and
published massive piles of information about toxicity, at least some of
which is germain to keeping aquatic plants.  Toxicity to high levels of
major and trace elements should be diagnosable (is that a word?) and we
should be able to get photos of plants that we can say with confidence
exhibit toxicity symptoms.

Deficiencies are a different problem.  My understanding (from reading in
the Krib, I think) is that most of our nutrient deficiency information has
come from a hydroponics reference.  I've found similar lists of symptoms
for hydroponics growers and for field crops.  What makes me a little
doubtful about further efforts in this direction is that a) aquatic
plants may exhibit somewhat different symptoms and b) many of the
symptoms that can be observed are very similar (chlorosis is chlorisis,
necrosis is necrosis, regardless of the cause) and not particularly
diagnostic.  The document on deficiencies in field crops was quite
specific that some deficiencies required a whole plant or leaf tissue
analysis before they can be diagnosed.

Can we really identify a particular deficiency without comparing analyses
from healthy and "deficient" plants?  Could some organization (AGA for
example) organize an effort to get such data?

Roger Miller