I think airstones or diffusers in buckets tend to be unstable on the pond bottom. Diffusers should have wide bases so it is difficult for them to fall over, tip over, or sit in an angled position. The pond bottom that has muck build-up is not the levelest of surfaces. The weighted airline exerts a "pull" on the diffuser, usually during installation. My experience indicates buckets are often on their sides.
An airstone or diffuser in the bottom of a cut-off plastic barrel (30-55gal) makes a lot more stable base for the diffuer.
Diffuser Marker Floats. One experience with a duck decoy as a marker for a diffuser resulted in the duck decoy always going in a circle when the diffuser was operating. Eventually the circling duck wound up the rope into knots which lifted the diffuser off the pond bottom. Hard to believe, but true.
