The two resistor values I liked were 047 and 010, way bassier than the 150 that was suggested. I started thinking about it more, and really want to keep the controls simple. So here is the current plan. Replace the volume pot with a push pull that switches between 047 and 010.

Edited this post to delete "Then, in the swimming pool, a two way switch between 047 and 150." I am not going to put a switch in the cavity; just stay with a push pull choice between the values I liked. If it does not work out, I'll just patch in a different resistor.