I have a swimming pool rope float attached to my diffuser with UV safe poly-cord. It floats a few feet beneath the surface so my dogs don't try to retrieve it and to avoid getting frozen in the ice. I wondered if it would eventually take on water but so far it hasn't in a few years of use. I use a garden tool to grab the rope.

Here's one similar to what I use, try looking for them at pool companies or marinas: http://spaandpooldepot.com/pentair-swimming-pool-rope-float-5x9?gclid=CIPywdqJ6b0CFcyhOgodgF4AfA


[Linked Image from i108.photobucket.com]