Sorry for your lost champ,
my opinion "Protozin" is to strong for these fish to tell you the truth, "Icaway" is probably your best treatment, but you should have rasied your temp to about 33-34 for 3 days and slowly lowering it after the 3 days, add a little salt wouldnt hurt, and important more oxygen so more air stones.
I remember i had whitespots on my old L204's about 2yrs ago and rasied the temp to 34 for 3 days and 32 after the 3 days then to 30 then 28 and when away - no chemicals - just a little salt and more oxygen.
Hope the rest are okay .