yup, different brands of ferts have different ingredients, a good example would be the tetra flora pride and sera florena which is nitrate and phsophate free compared to the hagen(?) and other ferts which contains nitrates and phosphates
im not really experienced with the hagen nutrafin ingredients right now and a quick google (im in the office right now cant really research too much) did not yield anything.
If your tank is heavily planted , high lighting and co2 enriched, or even just moderately, then dosing the recommended amount would not be enough