Yes, ppm and mg/l are the same measurement. Your 13.4 ppm is very high
iron. If you weren't using iron out, your softener would have loaded up
with rust (Ferric iron) already. Which it may be anyway. With that much
iron, I would expect IRB if not now, at some point in the future. Then
you will have an H2S odor. And all types of non-disinfectant type
equipment will fail.

Gary
Quality Water Associates
www.qualitywaterassociates.com