DIY trace element fertilizer

I've been looking around for a chelated trace element mix suitable for making
PMDD's, but unfortunately the only mix I could find contains about two orders
of magnitude too much copper.  So I've been thinking about mixing up my own
from the raw chemicals.

A while back, Shiao Wang posted a recipe for a trace element mix that looked
something like this:
EDTA sodium ferric salt (chelated iron)   40.000g   = 7.70% Fe  7.00%
MnCl2.4H2O   (manganese)                  10.000g   = 4.56% Mn  2.00%
H3BO3        (boron)                       3.000g   = 0.85% B   1.30%
ZnSO4.7H2O   (zinc)                        2.000g   = 0.73% Zn  0.40%
Na2MoO4.2H2O (molybdenum)                  0.250g   = 0.16% Mo  0.06%
CuSO4.5H2O   (copper)                      0.025g   = 0.01% Cu  0.10%
CoCl2.6H2O   (cobalt)                      0.025g   = 0.01% Co  
                                    total 55.300g

Assuming I've calculated the percentages correctly, Shiao's recipe is roughly
similar to the mix used in PMDD's (the exact values probably don't matter
much, just the order of magnitude of each element).

Notice that neither of these mixes contain Magnesium.  Neil Frank's nutrient
deficiency symptoms list notes that lack of Magnesium can cause yellow spots
on leaves, and Magnesium is one of the major incredients of the Duplagan water
conditioner.  Is magnesium deficiency likely to occur in aquariums?  Should it
be added to the fertilizer?

I requested a price list for various chemicals from a company in Auckland and
this is some info from it for those interested.  (all prices are in NZ$.  US$
will be about two thirds of this):

Chelated form:
Iron       1kg = $17.50
Manganese  1kg = $21.90
Zinc       1kg = $18.20
Copper     1kg = $24.00
Cobalt     1kg = $90.60

Other chemicals:
Zinc sulphate    25kg =  $26.30
Sodium Molybdate 25kg = $892.80
Copper Sulphate  25kg =  $52.50

They don't stock CoCl2 or MnCl2, but they do have:
Cobalt Sulphate    25kg = $795.80
Manganese Sulphate 25kg =  $32.50

I'm not sure what H3BO3 is in english, but these guys have:
Borax pentahydrate 25kg =  $36.50
Borax solubor (?)  25kg = $123.00
Boric acid         25kg =  $48.00

As you can see, these quantities would probably be enough to last multiple
lifetimes :-).  Even factoring in smaller quantities being more expensive per
gram, the raw materials will work out way, way cheaper than Dupla (10ml daily
dupla drops cost about $18 here last time I looked, enough to pay off 1kg
chelated iron :-))

Are the elements other than iron in the PMDD mix in chelated form also, or are
they using the same chemicals as in Shiao's mix?

Well, I'm off to the library to find some books on tissue culture.

 Len Trigg ===================================================
 Comp Sci Grad   DoD#1334   trigg at cs_waikato.ac.nz             
 Waikato Uni     GPX250     http://www.cs.waikato.ac.nz/~trigg          
 Finger trigg at jane_cs.waikato.ac.nz for PGP Public key