Hi Jeff,
The only plants that seem to be affected are the Microsporum pterous species although I have a large variety of other plants in the tanks including Limnophila aromatica, Hygrophila lancea, Bolbitis 'short form', Crypts (various) Ludwigia arcuata X repens, Ludwigia X Lacustris, Ceratopteris (two types), Marsilea minuta, Helanthium bolivianum "Vesuvius, Persicaria 'Kawagoeanum', and others. It could be that the Microsporum pterous are just the first to show extreme signs of the deficiency?