I thought I had looked through Dom's kefir site, and the bacteria counts for water kefir were lower than I expected. Let me look again and see if I can find the link--I wanted to replace our probiotic supplements with water kefir for the kids, but balancing the alcohol content and the amount they'd have to drink to get the bacteria count didn't seem feasible. Let me see what I can find.
ETA: I went and looked, and realized all I could find on his site was bacterial counts for milk kefir, and even that was lower than I expected, 5million cfu of lactobacilli per mL. I made the assumption that water kefir and milk kefir have equivalent bacteria counts, but I have no idea if this assumption is a good one. But 1 cup is about 240mL, so using these assumptions on bacteria counts (and I expect they can vary quite a bit from batch to batch, so I don't know how much store to put in these numbers), 1 cup has 1.2bil cfu's. But my Jarrow capsules have 3.4bil cfu's in each. I was bummed (then and now).
ETA2: Dom's site lists many types of bacteria (lactococci, leuconostocs... stuff I haven't heard of), so I just looked at the lactobacilli, since I think that's what our pills are. Yeah, I have lots of knowlege gaps to fill in.