Hi Phil,  Regarding your problem with sound levels in the room where
your bottle organ lives, I'm pretty sure that you have what's called
a standing wave problem.  The physical dimensions or properties of your
room are such that a resonance is created at the specific frequency of
that bottle.  If you can determine the wavelength of that tone, you
might be able to find some dimension of the room that resonates at the
right frequency.

The most simple case is having two parallel walls that are exactly half
the wavelength apart.  It could also be the floor to ceiling height and
it might be an harmonic (or N times the wavelength).  Try moving some
rugs or furniture around, especially if you have acoustically hard,
parallel walls/floor.

Regards,
Craig Smith
near Rochester, New York