Necro poison dagger question

Greetings All,

I am running a Necro and I am messing around with a poison build. I have a Grand Charm that has 15 poison dam over 4 secs, if I use “Poison Dagger” will PD overwrite the charm or add to it? I see no need to take up space if any poison charms will not work with PD.

Thank you all for any help!

Poison charms work with poison dagger, but they reduce the poisoning duration, so you have to stab more often.