liquid fertilizer question
I know almost everyone here who uses liquid fertilizers uses seachem products, but I cant obtain their products locally. I use a PlantGRO, which I am sure is a hagen product. Anyway the chelated iron fertilizer has magnesium, boron, copper nitrate and of course chelated iron in it. I was wondering if plants even use magnesium and boron and isn't copper harmful to plants? I was also wondering about chelated iron, everyone here seems to say it is overdosed and not necassary. Is this plant fertilizer worth using, or is it merely snake oil?