I got small amount of Na2 EDTA. Is this the same stuff as EDTA? I would like to use it to chelate my Fe fertilizer (2% chelated + 4% non chelated Fe). EDTA is in powder form and Fe is in solution. How should I dose EDTA? Thank you, Davorin from Croatia, from cold and windy town of Osijek (I kind of like this "around the world weather report" thing)