'...does it go to Eleven?'...
Evidently a high pH in the worm bin is helpful to get rid of mites & other 'chit. When I had an indoor bin to get started that was helpful, but even better was using cantalope pieces as "traps" or bait, then washing the mites off in the sink & re-use a few times. (my bin had waaaay to many red mites)
Another thought on your last comment is that it's the cast-off, excrement, which the worm moves away from or even pushes out of a burrow...(?)
(also, tolerances will likely vary with species for pH, temp, etc.)
loves the wormies