I hear so much about it but have never seen it so just trying to understand the physics of it. My take is that in theory, the salt is undermined so that the water meant to dissolve salt into brine doesn't actually touch the salt. In practicality, I cannot see how 200 pounds of salt can hang in the air above the water, supported entirely by friction/adhesion to the sides of the brine tank. If supported by pillars of salt, would not the pillars dissolve and the bridge collapse? Even if there was a cavity formed, would not the brine reach saturation with whatever amount of salt the water is in contact with?
Last weekend I let the salt level get real low as I intended to empty out the build-up of non-dissolvable material. This got me to wondering if perhaps this material could form pillars to hold up the salt. It never has for me, but it was quite a solid mass that was better not to be there. The mass also caused a dirty silt-like material to get sucked up the intake.
Anyway... this is the second time in 14 years that I cleaned out the brine tank.