My kettle is driving me maaaaad! I descaled it about a week and a half ago and it was fine after that. I only use filtered water in the kettle to try and keep it fur-free. Since descaling it 1.5 weeks ago, I've had to scrub round the bottom to get soft deposits of limescale off it. At this rate, I'm going to have to descale it once a week! Any ideas to keep my kettle's bottom fur free (other than chemical descaling!)?