My vote is for concept 1; it's a really interesting idea to fill the bowl with water. I like concept 2 visually, but the "+" only comes across in 2b, which I don't really like - too much blue. For concept 1, I much prefer b to a - the three filled bowls of a are overdoing it, I think. Maybe experiment with which letter should have the blue fill, as the d might work just as well. If you choose concept 2, I'd go with choice a, which is the best balanced in color.
As for the type, I like both your choices. Sophisto is pretty much what you want, something crisp and simple. There might be other sans-serifs that work just as well, but there's nothing wrong with it. Avenir fits concept 2 as well; it gives it a modern, pseudo-corporate feel, almost as if it were from a bottled water label. Overall, very nice job!













