I prepared the solution according
to the recipe that you did but I didn't use filtered air system.
solved EDTA in water added FeSO_4. 7 H_2 O after that and added this mixture to
the boiling solution.
I did it in this way and then cover it (with aluminum foil) for avoidance of
light, after 2 weeks now it's Purple. I had some rust too and it is normal as
- I didn't adjust pH at this step, also didn't mentioned in the protocol.
I hope it would be helpful for you.
M.Sc student of plant biotechnology
agricultural biotechnology research institute of Iran (ABRII)