My new house runs off a bore so I had the water tested to see if I needed to use a water softener. Turns out the water is very soft but also quite acidic: pH 5.37
The guy who did the testing said it was low but that I could wait and see how it goes before I put in any water treatment.
I don't really want to take a wait and see approach on my Alex Duetto.
Any recommendations? Should I be concerned about other appliances as well?
My water supply here is entirely rainwater - and the pH of that varies somewhat due to storage in an in-ground tank. The pH slowly rises in the tank, due to the masonry construction.
But over winter: the pH sits at just under 6, rising to 6.5 by mid-summer. All the appliances (kettle, espresso machine, dish washer and clothes washer) have used this water for 25+ years with no bad effect.
In fact - the bloke who came to fix the washing machine remarked how un-crudified it was after 7 years use.
Now, 5.37 is pretty acidic - pH is a log scale. If you were concerned about it being excessive, you could basically do what I've done: store it in a tank with something in said tank to adjust the pH. I'm basically thinking along the lines of a poly tank with some suitable rock/cement things in it That'd work, I'm pretty sure. Your test shows there is scope for more dissolved calcium, which is what you'd end up with if you chuck a besser block in a tank of that water...
Acid water will tend to rip the zinc out of brass, BTW. So if you have a brass boiler, this could be an issue. My espresso machines have brass boilers - and I have to say I'm not overly concerned. I would hope they've used de-zincification resistant brass.
Overall, I have to say I think I much prefer to have soft acidic water to the usual South Australian alkaline water that has enough dissolved solids to completely block a shower rose before you've actually finished your shower...