Not sure how much water is needed - I'll have to do some calcs later. I can only ferment 6 since it's in a 6.5 tub.
I don't have a way to introduce pure oxygen - I could do a bubbler or something but I would imagine that would introduce some nasty stuff to the fermenter.
Not sure why the OG is so high. It's an all-grain batch.
I think most of it is the boil off (/ not starting with enough during the boil).
I did a continuous sparge method that I think is pretty effective, so that probably contributed as well.