Arc blood mage build not triggering comets attack properly

Hello reader,
I've been playing arc blood mage since i started and after having stats high enough to trigger the multi comets attack it never does but Cast On Critical does not charge up fast enough to trigger it despite have the stats to make it so...
I can provide my gear screenshots if needed.

thank you and have a great day!

do you have enough instant blood leech? I suppose you use blood instead of mana.