I'm looking for ideas to use for open water students to take their minds off buoyancy while in the pool.
Interesting phrasing...I actually don't want my "students to take their minds off buoyancy while in the pool" but, to the contrary, be very aware of it. Once they are, in fact, aware of buoyancy control, then they can start towards the state of "unconscious competence" which allows them to expand their situational awareness.
OK -- how is this done?
From the very beginning, good buoyancy controlled is modeled by ALL the staff and the students are encouraged to experiment with the concepts.
Towards the end of their confined water time, they are, to a greater or lesser extent, drilled while being "encouraged" to maintain their place in the water column. Mask flood and clear? Better stay within a couple of feet of where you started. Air share? Ditto. Ascend up/down a line? You'd better be able to maintain a stop, rise a foot, stop, maintain, up a foot, stop maintain, down a foot, stop maintain, etc.
I've had them play games but, as far as I can tell, they get much closer to "unconscious competence" through drills and skills than tossing a toypedo. What is really fun is having the students drill themselves and then demand the staff do drills too.