Question on conversion

Hi I’m playing a Acid/Poison witch hunter and I have a question:

Ring of Steel does Pierce damage, the transmuter convert 100% Pierce to Cold, however I want to wear a medal that says: 100$ Piercing damage converted to Acid damage to Ring of Steel

then what damage is my Ring of Steel doing ultimately?

Should I get rid of the transmuter to make Ring of Steel do Acid damage? I like that transmuter due to the freeze effect.

If you use both the transmuter and your item, ring of steel will do 50% cold damage and 50% acid damage.
Since you’re an acid build I would recommend getting rid of the transmuter. The freeze is nice, but eventually it’ll get to the point where normal stuff dies so fast the freeze doesn’t matter, and anything tough is immune to the freeze.

Dlesar is correct, you will end up doing 50% of each. This is because conversion is always weighted to a 100% scale. You have 200% total conversion, 100 acid and 100 cold, but since it weights to a 100% scale the total 200% must be divided by 2 to yield a 100% conversion. 100%/2 = 50% so you get 50% acid and 50% cold.