Hi. I have ound a place that will sell me 100g of a Chelate trace element mix for $6.00!!! The contents of the mix is (7% Fe, 1.3% B, 2% Mn, 0.4% Zn, 0.1% Cu). Is this the stuff i want to use to make PMDD ??? If so once i make the 300ml solution up how much would i use in a 55 gal tank??? Also, would 100g of that mix last a while??? Thank you for the help, Chris aka,,,,Griff1324 at aol_com