# Water hardness measurements (GH / KH) for ashbeck, tap and filtered - what's 'good'?



## Jon V (Feb 24, 2014)

I want to get away from using Tesco Ashbeck water in my espresso machine (too much waste). I have a filter jug (BWT Bestmax) but living in a hard water area I want to be sure it's not going to cause scale issues.

I got this kit and ran a few tests: http://www.amazon.co.uk/API-General-Carbonate-Test-Kit/dp/B003SNCHMA

Tesco Ashbeck:

GH (general hardness): 35 - 55ppm

KH (carbonate hardness): 70 - 90 ppm

Tap water:

GH: 285 - 305 ppm

KH: 160 - 180ppm

BWT Bestmax jug:

GH: 70 - 90 ppm

KH: 160 - 180 ppm

So how should I be interpreting this? Are the levels from the jug "safe" to use?


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## Charliej (Feb 25, 2012)

It's the carbonate hardness you want to be worrying about and looking at those figures the BWT jug isn't removing any of that at all from your water, it would be interesting to know what it does actually remove.


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## Jon V (Feb 24, 2014)

This post on home-barista may give some explanation (the BWT is an ion exchange filter) but my own level of understanding is not enough to say.


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## CallumT (Aug 23, 2013)

Surely general hardness is simply a TDS reading and takes into account ALL the mineral content inclusive of Carbonate Levels whereas the second test is a Carbonate only test (should be lower than general hardness, as carbonates are a proportion of whats in the water)

If your titles were the other way around its clear to see that the BWT is exchanging the carbonate hardness for most likely more minerality; although saying this my inline BWT Bestmax Premium drops my TDS from about 135ppm (tap) to 120ppm (filtered)


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