Rol-Aids is the anti-acid that has Aluminum in it.

This thing sounds insane! But I've often thought about a marine RO unit for emergency purposes. I live near the ocean and have unlimited salt water available, so a way to desalinate it could be very useful. There are some portable units that can make dozens of gallons a day from 12 volt power, if you don't mind the cost. But they're beyond my price range, for now.