"deuterium accounts for approximately 0.02% (or, on a mass basis, 0.03%) of all the naturally occurring hydrogen in the oceans"
having the low as hell ratio is important, if you want, you could lower it from bobs... alternatively you could look at slapping water/hydrogen into a centrifuge (may need a few fluid boxes, or advanced chemical plant).
I like the idea though, i was kind of waiting to see if angel was going to do anything with this before i considered adding something similar to clowns nuclear or PCP.

As is, the ratio is 6000 purified water -> 5000 purified water + 1 heavy water. From what I understand the natural occurrence of deuterium in water is every 1 in 6400 hydrogen atoms is a deuterium, so this is a lot closer than the original 100 : 0.5 that the Bob's recipe was.