Shadow,
From what you're saying, it sounds like a piece of the puzzle is missing. If the increased acidity of your output is a new phenomenon, then you need to find out why the acidity has changed. Acid comes primarily from the stomach, and intestinal bile comes from the liver, but it is not acidic. If it were me, I'd take a sample of what you think is acidic and check it with a pH strip (available at any pool supply store). If it is highly acidic, then you need to talk to your doc and find out how to control that. Many people think they can reduce the acidity of what comes out of their stomach, like a buddy of mine who told me not to drink carbonated beverages because it would increase the acidity of my stool. He didn't know the body (stomach) works very hard to maintain a very specific pH before it passes the contents on to the small intestine. And unless something is wrong, that pH doesn't change much no matter what you eat. Sounds like in your case (if your output is highly acidic) that something is amiss. You also need to know that acid isn't the only thing that eats through wafers/barriers. It certainly depends on the barrier, but some react (break down quickly) when pure water contacts them, etc.
So first find out what your output actually is... pH test to start and then have your doc send a sample to the lab for analysis for actual chemical makeup. Then when you know what you're dealing with (if your doc doesn't prescribe something for you to help modify your output), contact the ostomy supply companies and find out whose product works best at dealing with the type of output you have. Sorry, I don't have a quicker answer.
Regards,
Bob