I think I've seen some solar bubbler/sprayers online somewhere or the other. No clue how well they work, or if they would push enough water to keep it circulating. Might be worth a try in a small container (half a wooden cask?).
Thanks for the complement, but must give credit to my son for the idea/design/build. It was all him, I just sat on the porch sipping mimosas with his girlfriend as he labored away.
