This Purifier should give you some more ideas alongside tqFan and Valinov’s suggestions. For me, i tried to lower it’s cooldown as much as possible and paired it with pure Elemental Grenado.
0.4 second cooldown
Don’t mind the Pierce damage shown. It is all converted to Elemental through global conversion.
I suppose you can convert the Fire damage off of Sigil of Consumption and pick up some Vitality->Acid easy enough on your belt/rings. Pair with 3-piece Radaggan and some support items and it could be sufficient but it bugs me that just barely missing 4-piece Radaggan misses some big bonuses to Sigil and above else misses out on green Sigils.
Other than that, I posted it in another topic but this was a random brainstorm I had for Acid Gandarr that remains untested: https://www.grimtools.com/calc/aZqEoPvZ