Tuesday, May 20, 2014 at 06:24
Give them a dose of household chlorine bleach (un scented, no other additives).
We use about 10ml per 100L of tank capacity every fill, but for a one off 'shot', use several times that, allow to slop about for a while and then drain.
Cheers,
Peter
OKA196 Motorhome
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816099