Which fertilizer/trace elements do you use?

I have a 150x60x60 cm (5'x2'x2') aquarium. Light: 2x150W MH; 
Water:GH ~14dGH, KH ~10dKH, NH4, NO2, NO3 (still) zero or almost
zero (NO3). CO2 injection - pH 7.3 (CO2 of about 15mg/l). Under-
ground heating cables 50W, large W/D filter. Some substrate additive
called 'Eurolit', looks like baked clay, very porous. Water temp 24

Plants: eight different Echinodorus sp., some Crypt. wendtii (not doing 
well), a whole bunch of other  stuff for a total of almost 30 species.
The tank was only set up ten days ago and almost all plants are doing 
extremely well, especially all Echinodorus and the Valisneria. The mexican
oak leaf is 'exploding'. I do have a slight green algae problem not quite
completely under control be the five Chrossocheilus siamensis.

So far I only put in some of Tetras Planta min fertilizer. A colegue 
suggested I should monitor iron levels, with the MH light and the CO2, I 
would probably need many times the suggested dose, especially in the 
beginning. It would also control the algae (?). He uses the expensive
Dupla stuff ($$$). Is it worth it? Who has experience with it? Is the
Tetra stuff equal? How does the iron complex stuff keep down the algae?
Oh yes, other than the siamese, there are only 14 red neons and one pair
of Trichogaster leeri.