On Wednesday, 7 October 2020 14:00:56 UTC+1, Martin Brown wrote:
On 07/10/2020 13:16, The Natural Philosopher wrote:
On 06/10/2020 20:26, AJH wrote:
On 06/10/2020 15:40, Andy Bennet wrote:
On 06/10/2020 15:32, tim... wrote:
My toilet pan has a stain below the watermark that neither bleach
nor readily available acid (vinegar) will remove

what stronger products are easily available that will remove it?

You need hydrochloric acid. Probably the strongest supermarket
cleaner with highest concentration of HCl is Harpic 10x, about a quid
a bottle. The stain is basically discoloured calcium carbonate.

Yes as has been said brick cleaning acid is the easiest obtainable,
main thing is to use little and leave long enough to neutralise
itself, it's fine in the pan but will react with any cement on its way
out if still active.

So follow it up with some caustic soda.

Bicarbonate of soda or washing soda is a lot safer to handle even if it
will fizz a bit.

Brick acid turns limescale into soluble calcium sulphate, and caustic
soda turns fat bergs into detergents and soaps. And turns brick acid
into sodium (bi) sulphate

Brick acid is hydrochloric - calcium chloride is fairly soluble whereas
calcium sulphate aka plaster or gypsum is only very slightly soluble.

Using sulphuric acid on limescale might flake some of it off but would
leave you with flakes of gypsum.

IME it does get it off, though a good bit slower than HCl. I presume it turns it into non-adhered powder or fine grit.


NT