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!
Possible centerpiece idea. Tie balloons to current vases Balloon Centerpiece using mason jars.like this idea you can fill the jars with whatever you like - Candy for kids, shells, colored marbles, flowers, themed items. A Good idea to shelf.