Re: PMDD Ingredients/PMDD and Light

To: Aquatic-Plants at actwin_com
Subject: Re: PMDD Ingredients/PMDD and Light
From: ac554 at freenet_carleton.ca (David Whittaker)
Date: Thu, 31 Oct 1996 02:59:48 -0500

Raul Andres Schmidt Hutchison asked.....

>After all the talk on PMDD last week I tried to see if I could do it. I
>could find most of the stuff but the element mix is not exactly what is
>required. The one I found was spanish made (called Trabecorp AZ) and had
>
>        7,5%Fe  0,65%B   0.3%Mo   0.28%Cu   3.5%Mb   0.7%Zn   EDTA

>        Some of the percentages are off and also the DTPA is missing. How
>crucial is this. Can the percentages be varied. How much?? Also, one of the
>main points in using this was to eliminate the algae that would keep showing
>up and end up all over my plants. I do not have CO2 injection however. Does
>the PMDD still work???

Looks fine to me. DTPA supposedly stretches the shelf life of the
solution a bit. As long as you do your weekly water changes, it is
less likely that any of the ingredients will build to concentrations
that would interfere with the uptake of other nutrients. I'd determine
your iron requirements and match the iron in the chelated mix to these.
There is nothing magical about the chelated mix that is mentionned
in the PMDD recipe. It just happens to be available in Eastern Canada.
Excessive copper is one thing that one would wish to avoid.

Pat Bowerman asked....

>Should PMDD's be kept in the dark? Does light break down the chelated
>iron?

Yes, light has an adverse effect upon the shelf life of the FeEDTA.

--
Dave Whittaker                       ac554 at FreeNet_Carleton.CA
Gloucester, Ontario                  dwhitt at magmacom_com
Canada