My water softener recently stopped drawing brine, which lead me to discover (after emptying the brine tank - not a fun activity) that under the brine grid, a layer of salt had built up and was preventing water from getting into the float tube (at least fast enough to keep up with the draw).
The salt in question is clearly precipitate, not pellets that were dissolved small enough to fall through the brine grid.
The only plausible explanation I can think of is that as the water supply changes from warmer to colder (mine gets quite cold in the winter), solubility goes down and salt precipitates out.
I've thought of drilling holes in the float tube just below the brine grid line, since I doubt the precipitate could get that high. Or, add a heating element and thermostat to keep the brine tank at a relatively constant temperature.
Any other ideas? Specifically ones that don't involve emptying the brine tank out each year to scrape the precipitate off the bottom.