Can I float candles in my pool?

YES.....but.....

Any candle that is designed to float, can and will float in a pool, pond or water fountain regardless of it's size.   But, here are a few things to consider before you light that wick.  

Pool pump off
Make sure your pool pump is off and any water features such as a water fall or mister system are off as well.  You want to prevent as much water movement as possible.  Hopefully mother nature is going to be on the lighter side too as wind and even a light breeze can affect how well the candles work in larger bodies of water.

Candles will gravitate toward edges or corners.
You'll need to come to terms with the fact that where you place your candle won't be where it stays for any length of time.  Floating candles may start the evening in the middle of the pool but you'll notice the little buggers bobbing along toward the sides or a corner only to rest there for the remainder of the night.

Coping
If your floating candle isn't specifically made for pools, you could end up with a blackened underside to your coping.
Candles 5-6 inches in diameter are a good size for most pools.

Clean up
If any water seeps in to the candle it may weigh the down the wax shell and sink a little in the water, making for irritating clean up as they could be hard to see.   They will not sink to the bottom as wax naturally floats but the weight of the water inside the shell will hold it suspended just below the surface.
Finding ways to anchor the candles is possible and luckily we have Pinterest to help with us that.

I now have floating rose candles available that are the perfect size for pools and spas.  They measure 5 1/2 inches in diameter with an 8 hour burn time.