It started working...
I made so many tests last days. I used only distilled water (even for washing), regenerated silver bath, diluted developer from 1-1 to 1-5... and 2 days ago I started seeing improvements. Now I use tap water, dilute developer 1-3, silver bath is clear with about 3-4ph. Pictures are ok.
Maybe this collodion needed a little aging, or something was in my tap water last days.