I heard back from Everpure on my question about the impact of the presence of both chloride and sulfates in water on the cutoffs for each in terms of corrosion risk. They answered with an explanation of the process (which I will omit due to the repetition of concepts from my original post), and this:

Everpure representative wrote:Chloride by far is the most important species here with sulfate a distant second. At this point in time there is no quantitative data to suggest exact amount in what ratio to be concerned with as it pertains to Claris or water chemistry in general. You can compensate for this pH drop by increasing the bypass setting until the resultant pH is at an acceptable level thus indicating a buffering of the acid produced and influenced by the chloride and sulfate. This is why water testing is important.

So it sounds like they basically endorse water testing for the presence of the ions and the pH of the output. Given that you've done that and it's rather low, I think I would stop using the water.

By the way, if you are using a Slayer now, it's worth mentioning that they also caution against chlorides in water. Their water treatment guide that came with the single group states that the most important properties of water are alkalinity and chloride levels. They don't provide cut-off levels for either, but they do say that chlorides encourage pitting corrosion, the type that can cause pinhole leaks in a boiler.

Thanks Nicholas, very interesting statement from Everpure. I'll setup the alternative filtration system and will check how that impacts the pH-level. I've looked a different types of RO-systems and the compact/ small systems usually don't deliver the required outlet pressure (around 2.5 bar) for the Hydra. The larger systems won't fit in my kitchen. Everpure offers a series of residential RO-system, but they are not available in Europe.

The Hanna HI 755 test revealed alkalinity level of 250 before and 120 ppm after Claris filtration.

It is clear from this thread that chloride and sulfate ions are a problem with SS boilers, above (somewhat uncertain) threshold levels, and at acid pH around 6 or less. The Claris Ultra has been designed to counter this effect, and purports to maintain alkaline pH of the output water, while maintaining the other benefits of the original Claris filter.

This filter, for some reason, is not distributed in the USA.

I found a vendor that has these filters at a reasonable price, and is willing to ship them to the USA.
http://www.andrewswater.co.uk/

I purchased a Claris Ultra 1500, and received the cartridge within a week, without a hitch.

I will test the filter when I do my machine service and filter changeout in the next 4-6 weeks. Hopefully, it will perform as advertised.

I probably need to replace my testing stuff before then. Does anyone care to PM me a link to an appropriate kit? Please, Thank you!

-Mike

I have a Claris system that I have yet to put into service.

I will do so shortly after I take delivery of my Vesuvius which should arrive in a week or so.

I literally stumbled onto this thread when checking back in a previous thread (thanks for the link Nicholas).

It seems clear I have every interest in monitoring my water closely (the Vesuvius has AISI 316L stainless steel boilers). Can someone recommend, or PM me the most appropriate testing kit to pick up?

My municipal water has low chlorides and sulfates (11.5 and 47.5 ppm respectively).

Thanks, this is a great thread.

You can go really nuts with water test kits from Hach, but I think the Aquarium Pharmaceuticals Aquarian Freshwater GH & KH Test Kit is plenty good. Just make sure your KH stays at or above about 50ppm, regardless of what GH is, and I think that Claris should work very well.

It does make me wonder about the sulfates, however. According to Everpure, they are low enough, but I would guess that they may contribute to lowering the pH. As a result, you might consider dialing the system to a slightly higher KH to buffer the pH better. If you are able, I would definitely recommend removingthe E61 group mushroom every few months (at least at first) to double-check that you have no evidence of corrosion or excess scale accumulation.

Thanks Nicholas. Very helpful. I will definitely remove the E61 group from time to time in the first year or so to follow its status. I've not had an E61 grouphead machine before (but have always admired the design), so I've been reading over threads etc. on how to look after them. Also on caring for a reservoir as I've always had plumbed in machines but the Vesuvius still makes use of a reservoir even if it is plumbed in to take incoming water pressure out of the equation for its pressure profiling.

Dave

In reality ion exchange water softeners are a (very) bad idea for any coffee water. The so called weak acid cation ones are an even worse idea than others because they remove carbonate and bicarbonate from the water. Other water softeners replace calcium and magnesium with sodium, and by their very design increase chloride in water--that is exactly what one does not want! Chloride is one of the worst things to have in water because it strongly enhances corrosivity.

Again there is FAR more Ca and Mg in the coffee beans than in the hardest water used to make espresso with them! Probably the least corrosive water is water that is about 1 millimole per litre of HCO₃⁻ and about 1 part per million of phosphate without the whole periodic table of pollutants. This is close to the bicarbonate concentration of slightly hard water, but it will not produce scale, and the oxide coats on copper and brass are about optimised at the pH of such a solution. It also buffers the water a bit to reduce acidity of the espresso.

1 mM water has 100 mg of potassium bicarbonate or 84 mg of sodium bicarbonate in it. 1 ppm phosphate is only 1 MILLIGRAM per litre!

rpavlis wrote:In reality ion exchange water softeners are a (very) bad idea for any coffee water. The so called weak acid cation ones are an even worse idea than others because they remove carbonate and bicarbonate from the water.

Except that in the real world every water treatment method involves compromises that may include cost, space, water waste, environmental damage, input and output. Anyone drawing water from a municipal water system (or from most bottlers for that matter) is dealing with constant changes. So, you decide what level of compromises you can live with and then forget about them.

In my many years of reading online forums, the number of complaints about excessive scaling outnumber corrosion complaints on the order of (rough guess) about 50 to 1.

Anecdotally, in five years of continuous use of a GS/3 with a Claris, we have had zero scaling or corrosion problems. FWIW, my wife, the (retired) water treatment chemist is fine with our treated water, which she tests every few months.

This used to be an overlooked subject in the forums, which I think has now become possibly a little obsessive.

Sorry if you posted this, Marshall, but what are your water treatment specs (values)?