Are all EDTAs the same?

  • Thread starter Rapayich
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Rapayich

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Hi,

I am making my own fertiliser solution. In doing so, I am considering multiple different brands of EDTA Copper, Zn and Manganese.

However, I notice discrepancies in the stable ph ranges of the same EDTA nutrient. For example:

Brand A EDTA Copper is stable between pH 1 - 10
Brand B EDTA Copper is stable between pH 4 - 8

Is the wider ph stability of Brand A a marketing tactic or a legitimate figure? In my head they are both EDTA copper so should be stable in exactly the same ph ranges. Possibly Brand A is stating the stability range in which there is still some chelation and brand B is stating the pH range in which there is full chelation?

Thanks
 
mysticepipedon

mysticepipedon

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Someone here might know the answer to this, but you would be better off doing some independent research than asking a chemistry question, with little relevance to growing cannabis, here. The American Chemical Society or a similar professional organization might have a Q and A service.
 
Z

Zill

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Howdy Rapayich,

EDTA or EGTA have varying degrees of ionization, # neg charges. the number of ionizations or negative charges is entirely dependent on pH. EDTA can bind mono, di or trivalent cations. The pH ranges suggested by the vendor don't make sense. Unless they are using the chelator to bind things other than Cu. Look at all your grocery items and notice the number of times EDTA or EGTA is used as a preservative.

Why ae you adding Cu?

Zill.
 
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