Rollitup

New ones have a lighter colored pit than used ones. My recommendation for burn in is to be sure you run it for at least 30 minutes, may as well be a full cycle. Just don't short cycle them.

Ok..., so I'll just run it on an 18 hour cycle like the norm and I should be all set.. I am looking at the pit now and it is mostly white except for the part nearest the base is slightly tan. There are also some fragments of glass in each one but I can't tell where it could have come from, is that normal?

That sounds like a new one.

Yes. As weird as it sounds, the loose shards of glass in the outer envelope are normal, lol They stay out of the way in the required vertical orientation. Base up or down is okay.