ok, i just added 1mill of vinegar to a litre of tap water i will check it an hour. I did check tap water that had been left for 24 hours and it was no different to the fresh BUT it is not easy to distinguish between the colours on the chart i have, some of them are hardly different between 7.2 to 7.6 will post a picture later with the result of my vinegar test.
cheers
a
cheers
a