@Faebinder this is one of my major pet peeves! I have my airlines tucked behind rocks, but every now and again it comes floating out and up or I get my foot or net or something else caught on it and pull it loose and then it floats until I can get back in the pond and secure it again. Like
@mrsclem said - weighted line is the permanent solution but it's pricey. Why, I don't know. It seems like it would be a simple matter to simply make it heavier! When I need to replace my lines, I'm going to bite the bullet!
Second aeration pet peeve - air stones that ALWAYS land upside down when you toss them in the pond. Why aren't they bottom heavy?? I had one pond guy tell me to just secure a rock to the bottom with some rubber bands - I was like "really? Someone can't figure out how to INCLUDE WEIGHT IN THE DESIGN PROCESS?!? haha! I get rage-y about dumb stuff like this! (Don't even get me started about people who drag their junk to the curb on Friday - when trash day is Thursday. So now we all get to look at your old couch/washing machine/mattress on the curb for a WHOLE WEEK! )