On the off chance that you aren't messing with me
, it's the process of removing mineral deposits left behind by the water. It's only the second time that I can remember doing it, but the "Descale" warning popped onto the screen this morning. It went away, so I'm guessing that it was a glitch, but I did it anyway. All I have to do is fill the water tank with vinegar, run a tank through the machine, let it sit for a while (so the vinegar stays in the internal reservoir for a bit), then run water through it a few times to get rid of the vinegar. Really easy.