I did a search and found a few threads on keeping ducks out, but the suggestions really seemed hit or miss.

I chase them away if I see them, but it's obvious from the mess they leave behind that they just come back when we are not at home.

Some of the suggestions I read were:

Run string across the pool (our pool is too big for that)
Dogs (not an option for us)
Various floating items (seemed really hit or miss, but I'm willing to try; what kind of float would work?)

Anyone have success keeping ducks out of the pool?