I recently joined the forum and have benefitted hugely from the wealth of information (felt pads under the feet of a heavy machine have already been a big help).
I have been using a 50:50 mix of Tesco Ashbeck and Volvic (hard tap water where I live) whilst I decide on a more permanent solution for the new machine I purchased last week. I decided to do some API GH and KH tests to see how the expected hardness and alkalinity based on the labels compared to the API test results. Based on some of the previous water posts, I understand there may be some variances in the actual levels compared to the figures shown on the Ashbeck and Volvic bottles.
I initially used 20ml water samples but then followed up with larger 40ml samples to help increase accuracy. For completeness, full test results were as follows:
Tesco Ashbeck - 40ml sample
GH test 49.22 mg/l : 22 drops in 40ml water (stopped at the first sign of colour change from orange to green). 22 drops / 8 = 2.75 drops per the API GH & KH conversion chart = 49.22 mg/l GH (expected GH 41.88 per the label information entered into Rob’s water spreadsheet)
KH test 24.61 mg/l: 11 drops in 40ml water to turn from blue to yellow (stopped at first colour change). 11 drops / 8 = 1.375 drops per the API GH & KH conversion chart = 24.61 mg/l KH (expected KH 20.50 per the label information entered into Rob’s water spreadsheet)
Volvic - 40ml sample
GH test 73.83 mg/l: 33 drops in 40ml water (stopped at the first sign of colour change from orange to green). 33 drops / 8 = 4.125 drops per the API GH & KH conversion chart = 73.83 mg/l GH (expected GH 62.91 per the label information entered into Rob’s water spreadsheet)
KH test 62.65 mg/l: 28 drops in 40ml water to turn from blue to yellow (stopped at first colour change). 28 drops / 8 = 3.5 drops per the API GH & KH conversion chart = 62.65 mg/l KH (expected KH 60.69 per the label information entered into Rob’s water spreadsheet)
For information, the smaller 20ml test samples showed Tesco Ashbeck as GH53.7 and KH26.85 and Volvic as GH71.6 and KH71.6 (same result for both GH and KH using smaller 20ml sample).
Not sure if this will be useful to anyone else, but just thought I would share the test results (to check for any inadvertent errors that I might have made in testing) and to highlight some of the issues faced when using bottled water. If anything, the tests have confirmed the need for a better solution, given the potential inconsistencies with mixing bottled water and help reduce plastic waste.
If I get an Osmio Zero, would it be enough to empty and refresh the water in the service boiler (125c) monthly and also draw 250ml from the HW tap post milk steaming on a daily basis? Would it still be advisable to do GH and KH tests on the water from the service boiler at some point or will refreshing the water regularly be enough?
