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Cyanobacteria, Algae, Dissolved Organic Phosphorous, Iron, Chelates
Thank you very much for your response Mr. Miller, I appreciate it. I'd
appreciate your feedback IF you see enough of interest to get you through
this posting, and anyone else as well.
-Organic phosphorus could account for some of the variations that are
-reported. More important I think is the fact that phosphorus levels aren't
-always the growth-controlling factor, and when it isn't the controlling
-factor it can reach fairly high levels -- say, 9 or 10 ppm -- without
-causing problems. If it is the controlling factor then problems might
-appear at comparatively low phosphate levels -- easily as low as 0.2 ppm.
-Whether or not phosphorus is the controlling factor depends on other
-factors in your tank.
I'm attempting the phosphate limiting approach and don't know if I've
ever achieved it.
I'm wondering, under that approach, does a significant presence of cba,
or say cba on glass in the open, above leaves, simply indicate that too much
P is in the water column, and must be reduced, say through improving plant :
fish ratio, assuming that all other parameters are as they should be?
I'm still learning how to handle all of the parameters that I've found
out about on this list, and how to provide them as stably as possible, and
actively look for things I might be missing. I've had my plant tank for
just over a year, and only found out about this list, and 'The Krib' a few
months ago. My tank conditions have been changed alot -usually more than one
thing at a time- because I had a catastrophic level of cba and seemingly alot
had to be done. Things are better now but still bad. So,I don't honestly
know if my observations throughout this period are sound enough to tell me
anything or justify putting these questions in front of everybody.
My P levels have read very low - they look to be around .00 - .05ppm on
my Seachem kit. (My r/o and plastic-jug Sparkletts distilled read the same,
but it did read higher when I tried dosing P). It has a continuous range
through those levels and beyond, but I have a hard time judging it precisely.
Maybe those levels are more significant than I thought, or maybe I'm not
reading the kit well. Or maybe another kit would be better. But there were
periods when I thought I had too much P limiting because plants looked P
deficient (heavy lower leaf loss- but no pinholes, no side branching - later
seemingly totally reversed when dosed P) yet still heavy cba and a little
And I remember seeing a reference here,to an article on cba which was
reprinted in TAG. that described increasing levels of cba below a certain low
level of P (inorganic?- I wonder). I am ordering the back issue if it is
available. The author reported that cba seemed to be able to survive at
lower levels of P than some plants and that .2ppm was too low for some.
Maybe in those cases, perhaps under bright light (which I had), a substrate
source must be available so that even lower levels can be maintained in the
water than the cba or algae require.. But then what about non gravel bound
plants like java fern or Riccia? Can they be grown under a P limited regime?
Or perhaps the cba and algae are living off of something else? Is P
really the limiting factor in P limited tanks or is something else underlying
it? I still don't understand the cause of their increase from fe dosing. Is
it the fe or the chelate? Are edta or dtpa or humins a P source, or do cba
live off of them?
I have been wondering if cba and algae could access P in leaves
parasitically; and if low P levels could injure plants making them more
vulnerable to attack; or if they might even lose their P, or something else
the cba can live on, into the water even before they look like they are
dropping leaves? Then I saw the 'Phosphorous and Phosphorous Control'
postings and got to wondering if organic P was an important factor. Also,
when looking into Hach kits I found that they have a kit which can read both
inorganic or total P. Its twice as expensive as their inorganic-only kit.
So I was wondering if that would be helpful or not. I'd rather not buy
either if I don't need them because money is tight.
So those were the questions behind my original posting which I hoped to
understand better before I buy an expensive test kit, and try another super
heavy plant load phase. Am I spinning out into la la land? If proper P
limiting conditions exist uniformly throughout tank, does significant cba
presence simply mean that something must be done to reduce P? And is cba's
presence a good enough point of reference that another test kit is
Any feedback would be greatly appreciated if this posting warrants it.
Too much? Half baked?