charles_reed
Well-Known Member
I've found sulphamic acid much less aggressive than any of the inorganic acids and more effective at moving calcareous scale.
I now use it for the toilet (but also take the pipe out and beat it every 3rd year), clearing the engine heat-exchanger. cleaning off the log paddle-wheel transducer and de-furring kettles.
Whilst you can buy it pure and unadulterated, http://www.amazon.co.uk/Bonnymans-Sulphamic-Acid-Sulfamic/dp/B00BY3UMVY
Fernox do a crystalline form which dissolves to a yellow solution when active and goes red when the H+ has all been used up.
http://www.fernox.com/files/Fernox/Content/PDF/English/DS3 2kg new.pdf
OK with silicon aluminum and most grades of aluminium used for marine use, but produces a pretty display of bubbles on non-anodised duralumin. Also don't use on plated plastic - cleans it superbly, so well that the plating comes off in your hand.