"Has anyone run into the following problem?  The float moves freely
within the tank but doesn't register anything other than green (100%
full).  Over the winter I lengthened my pump hose (so that the pump
would sit flat within the tank and not leave any water un-useable)
but other than that I've not modified anything else in the water
system.  The float was sitting at the bottom of the empty tank last
time I had it open (with green light illuminated on the gauge)."

I'm going to pass on a "fix" for this problem that people who live where
glacier water
exists use: put a tea spoon of table/sea salt in the tank then fill it. Some
water in
some locations do not have the necessary salinity to act as a good
conductor.

bob