I'm sure there have been several discussions of my question, but my searching hasn't turned up a definitive thread yet, so I'd like to ask here: What are the safest and most dangerous inks for pens with rubber ink sacs? And also for Parker Vacumatic diaphragms?
I have a bunch of samples of Pilot Iroshizuku inks I've been using, and I assumed these would be safe inks due to their generally excellent reputation, but in a thread here, post #45,
there is reference to a claim that PI and other Japanese inks are relatively alkaline and that this is bad for latex rubber. I'd like to know if I should remove these inks from any sac pens or Vacs I own and use other inks in those pens henceforward.
All experience-based observations on these or other inks will be welcome.