better still, if you are in a hard-water area get a water softener fitted. there will be no more limescale gunking up your facuets, shower, toilets, sinks and bath... and no limescale to destroy washing machines and dishwashers either, and you wont need to use salt. plus you can use half the amount of detergent! likewise in the shower/bath you can use use far less shampoo, and it'll make your skin feel much better...

disclaimer: not a water softener sales-person, i just live in a hard water area and would not ever live without a softener again. everyone should have one.