Tesco Value thin Bleach

[Skvez]

This is unscented Bleach (suitable for water purification).
Bleach is usually 5.25% or 6% Sodium Hypochlorite, this "Thin" Bleach is "less than 5% Sodium Hypochlorite" whatever less than 5% means (strictly speaking 0% is still less than 5%).
However it's only £0.29 for 2 Litres
I guestimate that that's good for about one years worth of water purification for one person.
Ironically this price is less than Tesco sell 2 Litres of bottled water for.