While we do not have any specific answer to how the LevelGuard reacts to the buildup of various materials, it will handle a certain amount of buildup. Generally, this highly dependent upon what the build-up material consists of. For a non-porous, non conductive material such as peanut butter the thickness would be 4 to 5 mm. For a material that soaks up water as it sits it would be considerably lower. For more specific answers, you might contact LevelGuard tech support at (877) 342-3261.
As with any sump pump system, all manufacturers recommend that your system be inspected every 3-6 months to insure that they are operating correctly and that the basins are free and clean of any debris that may impede the operation of the pumps or float switch.