Holy hell, thats a lot of water. I would, if the owner wanted US to do it mind you, try a combination approach. First drill some holes in the concrete, maybe 2-3 holes per side, and maybe 3-4 inches deep. Install drain tubes to help you find where the water is coming from. If you have reason to believe it is from the floor, do that as well. Then get the liquified bentonite and inject it into the holes with water running from it. DO NOT INJECT INTO THE DRY HOLES. Check your progress by coming back, maybe a week later, and see if the "dry" tubes now leak or not. This will let you know if you are chasing your tail or not. If you have substantial success with step one, feel free to inject into any remaining tubes, then finish with a skim coat of the xypex product. That was the skimcoat i was talking about, seeing the name jarred the old head around.

This exact process was dne up in seattle on a job that was actually below the canal water table, not 20 feet from our pits. Took the concrete fellas at least 4 weeks of work, usually allowing 3 days or so inbetween to chase it again. In talking with them he said he regretted not injecting into the walls sooner, he had tried, and failed, to skim for the first 10 days or so.