Well, EDTA is Ethylene-Diamine-Tetra-Acetate, a common chelator used in the laboratory (also in fertilizers as a source of chelated iron, I think). The question about ppm (with respect to Fe) can only be answered if we know what iron sulfate was used: Iron(II) = FeSO4 or Iron(III) Fe2(SO4)3
Iron(III) would be my guess.
Based on that you can calculate how much Iron you have in the solution. The problem with mixing the chelator and the Iron sulfate is that it might fall apart pretty quickly in your tank because the affinity of EDTA to Mg and Ca is very high and might displace the Iron depending on concentrations...