Carolyn:
As a general rule the practice of trichrome stains suppose the use of an
iron hematoxilin if you like to preserve good quality nuclear stain. Alum
hematoxilins
canīt stand the use of a combination of two acid dyes,
so -no matter what trichrome you are executing- use an iron one  like
Weigert (Lillieīs modification).
Carlos,Montevideo,Uruguay.