On Mon, 07 Aug 2006 10:33:21 +0100, Darren Clarke wrote:

I have a thick limescale problem that domestic cleaners aren't shifting so
I'd like to use one of the more heavy duty cleaners, but I don't know
which one to buy or how to use it.

A good heavy duty descaler is Fernox Descaler, it's sold at Homebase among
other places and is intended for descaling of boiler systems and pipework
and for heavy duty industrial and domestic descaling. You really don't need
an aggressive acid such as hydrochloric (muriatic) acid which is available
from some suppliers. Sulphamic acid which is the acid used in the majority
of domestic descalers is perfectly adequate.

Fernox Descaler is sulphamic acid crystals with a corrosion inhibitor and
an indicator dye to tell you when the acid has been used up. It coems in a
large tub and has instructions on the side of the tub. In general, wear eye
protection when using the descaler and rubber or plastic gloves as a
sensible precaution.

Vinegar won't do much good, not even if you obtain a higher strength
solution of acetic acid, and the fumes even from household vinegar will
make it unpleasant to use.

Read the instructions carefully before use and in particular note the
requirement to add the crystals to water and not the other way around.
You'll need a large plastic jug and plastic or wooden spoon for mixing, and
it's best to dissolve the crystals in lukewarm water.

I tend to keep an old domestic descaler bottle and refill it with Fernox
Descaler solution, because it's a fraction of the price of the stuff in
supermarkets which is mostly water, perfume and a trace of sulphamic acid
and detergent.