What's that Lassie? You say that Too_Many_Tools fell down the old
rec.crafts.metalworking mine and will die if we don't mount a rescue
by Tue, 24 Nov 2009 20:42:31 -0800 (PST):

I am looking for ideas for an adjustable sump pump switch setup that
one can adjust for different water levels, handle two different pumps
AC/DC, nonfouling with regards to algae/mold and be used to activate
an alarm to notify the owners that the pump(s) are running.

I've seen in the Granger catalog, a level switch that is used with a
float on a rod. The switch looks like a standard pressure switch
housing, but it has a metal tab that sticks out. Your float rod goes
through this hole. When your float rises, a collar on the rod
contacts the bottom of the tab and lifts it up, turning on your pump.
A second collar above the tab will turn off the switch when the water
level goes down. This arrangement allows you to set the start and
stop level independently. You will need to supply the float and rod
and some means to keep it vertical.

OR...

Also from Granger(and others) you can get small float switches that
can be mounted on the end of a length of pipe. They can't handel much
current, so you will need to use a relay to control your pump. I
think they are just reed switches, with a magnet on the float.
Adjust the position of the switches to set your start and stop levels.
--

Dan H.
northshore MA.