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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.

(excerpt:)
-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 
green algae.
  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 
unnecessary?
    Any feedback would be greatly appreciated if this posting warrants it.  
Too much?  Half baked?
    Thank You,
    Zach K.