RE: PMDD slowly getting the ingredients

Dear James,

  Makeup of Manutec Trace Element Mix - (South Australian company)

  Sulfur as sulphate              6.29%
  Calcium as calcium carbonate    10%
  Magnesium as magnesium sulphate 3.62%
  Maganese as maganese sulphate   2.88%
  Iron as iron chelate            2.73%
  Copper as copper sulfate        1.25%
  Zinc as zinc sulfate            1.00%
  Boron as sodium borate          0.09%
  Molybendium as sodium molybate  0.0038%

I'm a little worried about using the Manutec mix mainly because of the 
copper concentration which I beleive is a little high. It's about twice 
that listed in the PMDD recipe. This might adversely affect your 
livestock and in particular your invertebrates if you have any because 
copper is relatively toxic but I don't have any numbers as to its 
acceptable levels.

Also, I think the Manutec iron chelate has only EDTA and no DTPA as its 
chelating agent. I don't know how this might affect its performance.

I have just finished talking to Manutec, and they have given me some idea
about the levels of Cu. They suggest by the time the trace element mix 
has been added to the aquarium water, the Cu levels will be rather small,
and below levels that could be harmful to fish/invertabrates. 

They also suggest not just using KNO3 for addition of nitrate, but to use a
combination of KNO3 and CaNO3. Does anyone have any thoughts on this?

They also suggest that the main differences between EDTA and DPTA 
chelates, would be the pH at which activation would take place.(ie the
pH at which the plant would be most able to use it up) (Appologies for 
the possible misuse of terminology) 

They said that the small quantity should be compensated by the addition of
additional iron chelate, (FeEDTA) which they have available as a separate
product labeled as 13% FeEDTA, and add it in quantity to take the level up
to the level described in PMDD (ie 7%Fe).

As said by Paul earlier, the CaCO3 in this mix is in such small quantities 
compared to the normal buffering capacity (aka alkalinity / KH), that it 
should not be a real problem.

What do people think?

Marque Crozman