Personally, (and I do mean personally, since everyone has their own preferred way to root), I would get them out of water, and put them in some damp sphagnum moss, or better yet, moist coco-coir (you can get it at the pet store). Generally goopy stuff in water is going to be either a) bacteria, or b) algae. Neither will necessarily hurt your cutting, but it is possible. There's all kinds of good threads on rooting, just check out the search function.