Andy Dingley wrote:
On 1 Mar, 18:38, JimK wrote:

with the bleach thing you could probly calculate the likely
time/"number of cylinders worth of water" to dilute however much
bleach you put in down to "nothing".

Read Treloar for how to do it properly: Quantities, times, clean out
afterwards.

I googled.

http://www.amazon.co.uk/Plumbing-R-D.../dp/1405139625