We have a salt-based water softener, and I've been using this treated water in the boiler for years. I have a feeling that this is not a good idea. Two things that have surfaced and made me concerned: 1) After installing a new copper water pipe in the boiler, it immediately turned black, and a flush of the group head always produces gray water; 2) The site gauge cover (not the glass tube but the acrylic cover) ha s a lot of tan corrosion on both ends that does not come off easily (or at all) and the acrylic cover is being eaten away by this build-up.

Is it possible that the softened water is causing these issues? I think that when I first bought the La Pavoni Millennium I used distilled water. For reasons unknown, I stopped buying it and started using tap water.

Obviously, we can't taste the salt in the softened water, but I suspect that the trace amounts of salt are causing issues. Any thoughts other than I'm an idiot?

I'll answer my own question (which it seems I do a lot in this forum): Yes, regular softened water (not RO water) is ok. Filtered is better. No idea what caused the corrosion of the sight-glass cover.

Your water may have high levels of chloride ion. Chloride doesn't promote scale formation, but it does promote corrosion. Self regenerating salt-based water softeners, when flushed, discharge chloride into the bypass circuit into the house drain and thence into the water treatment plant or your septic system, in either case getting into ground water.

You should check your water supply (municipal or from your own well) for chloride levels.

I see that the OP is in the Tampa area, and there are some wells on that aquifer that do have fairly high chloride numbers, mostly due to seawater incursion. As Pressino said, may be worth checking out. If your chloride ion is high, you probably want to go back to bottled water, or purified water that you spike with a little bicarbonate. To remove chloride using a filter system your only practical solution would be RO.

As others have said, using a properly functioning conventional salt based water softener should not make the water any more corrosive than the same unsoftened water would be - - conventional softening does not change the pH nor the alkalinity. People used to believe that softened water was more corrosive because it didn't lay down a layer of 'protective scale.' That idea is pretty much debunked, especially for espresso equipment. Having limescale deposits does little to protect against corrosion, and since buildup will require periodic descaling with harsh acids, the overall effect of scale prone water would be an increase in corrosion risk. Non-scaling water with little or no chloride and 40+ mg/L alkalinity is the ideal for avoiding corrosion in espresso equipment.

As others said, that brass dipper tube, as well as other brass or copper surfaces inside the machine ideally will develop a thin surface layer of dark copper oxides. Unlike limescale, which is uneven and porous, that layer is protective and a good thing. Harsh descaling will remove that layer.

Pat
nínádiishʼnahgo gohwééh náshdlį́į́h

Navajo Nation?

Back to the water...
We're up here in Vermont for a couple of months and a flush here produces clear water. I don't know why the grouphead flush in Tampa yields gray water. However, the insights about high chloride levels in the Tampa water have convinced me to use bottled water when I return home. I'll also order a new sight tube cover and see (over time) if it corrodes with the filtered water. And, yes, I do not know how the top and bottom ends of the cover attract the tan corrosion. What I do know is that the original cover was glued in at those points and some glue *may* have been left chrome end pieces. Again, a mystery.

lmolter wrote:Navajo Nation?

Not a member, nor a speaker. I once had a bike racing buddy who tried to teach me a little but to no avail. I do remember gohwééh (coffee). I used to work in Crownpoint NM and am an admirer of the area and culture.