I'm using auto crafting to produce Hydrofluoric acid and it appears to use a random amount between .088-.1b of sulfuric acid. This results in a random amount of sulfuric acid slowly building up in my machine.

This is intended by Mekanism. I know it's really stupid and annoying. The solution is probably to just constantly export sulfuric acid with a crafting upgrade, then have the crafting pattern just be fluorite.