So I'm hoping this is a moment of idiocy that's easily remedied. I set
variables, one in the first frame of each slider:

Water slider: this.percwet=0 ;
Temp slider: this.perc=0 ;

And then there's a whole load of code that links the percent along the height
of the slider to a frame in its corresponding movieclip.

I can use either slider to control either clip, but only one at a time. It
will only let me set "perc" or "percwet," but not both at once. I tried
setting the variables using different scripts and with different variable
names. http://gryphus.googlepages.com/sliderfla.fla
Either I am missing something obvious, or my install is funky... this FLA is
the third time I rebuilt the movie.