Does anyone know what the "filler" in Plantex is?
I have the ratios if micros there but am unsure of the filler

Filler?

Namely SO4's, ETDA etc.

It's not pure Fe, Mn, Cu etc

Regards,
Tom Barr

Tom,

That's what I thought, or sodium.
I'm interested in having micros mixed for me with a composition similar to Plantex. I wonder if KNO3 wouldn't make a better "filler"

No, KNO3 is not a filler, it's just a nutrient.
ETDA and other items allow the metal salts functionality.

Try dissolving pure Fe, a nice cast iron version.
Then try dissolving FeSO4.
You need that type of compound, it's not just "filler".
Pure solid elemental forms are dangerous, hard to use, dissolve etc.
Potassium metal is explosive/burns when added to water.


Regards,
Tom Barr