Economical descaler?

Yes, it does work and the Sulfate will come off a a precipitate, but the reaction is slowed down by the film of Sulfate partly stopping the acid getting to the Carbonate, particularly on a hard substrate like limescale.

So yes, if that's what you have to hand, use it (carefully), but if you're starting from scratch, there are better options.

Cheers

OTOH it's a more concentrated acid than the other options [that I have here, ie HCl, acetic, phosphoric, citric], hence it does work as quickly & effectively as the others.

NT

Buy a tub of Fernox DS3. Should cost less than £20 and will make up over

I'd wondered about sulphamic acid as an alternative to citric, that's a surprisingly reasonable price for a reputably branded product, and it includes a corrosion inhibitor.

Thanks to all for the comments. Personally, I would be reluctant to use hydrochloric acid on a kettle element which (I guess) could have stainless steel cladding because of the risk of stress corrosion cracking.

So does Swarfega. I've never understood why.

Something that doesn't dissolve the chromium plating on the element might help.

In a world full of moving goalposts a punt in any direction will score a goal.

I use DS3 for this - sulphamic acid works very well, and causes minimum damage to other things. DS3 also includes an odour so you know it's there, and an indicator dye so you know when it's used up. The dye can stain other dirt remaining which is not soluable in acids. Whilst you wouldn't deliberately drink it, people often do accidentally when it gets left in a kettle or coffee machine, and it's not a problem in small quantities. (You will notice something wrong if you add milk and there was still any trace of sulphamic acid present, as the milk will immediately curdle into a lump at the bottom, and fail to whiten the drink.) You should avoid breathing the spray given off by fizzing scale, as in airosol form it can cause a fluid build up in the lungs some time later.

The indicator is another good point in its favour, in the modern Earlex steamer it is difficult to see the element. Point noted about aerosol, shouldn't be an issue with the Earlex because that has a float operated flap valve across the filler. Will be interested to see how it performs.