Helium filled balloons tied to weights in pool. If you want to create the illusion of floating balloons use fishing line which is virtually invisible. (IDEA- Could also ADD some glow sticks so that the balloons GLOW over the Pool at NIGHT!
Another option of floating candles in the pool. Also, since we'll be dancing by the pool, I'd like the area to be super dim lit. What do you think about these lights overlooking the pool? The only other option would be to light the area up with candles?