Hello!

Long-time lurker. First-time poster.

I recently and rather impulsively picked up a Linea Mini to replace a HX machine.

Obviously, I understand the risk that hard water poses to any espresso machine. But I have to say that beyond that, I'm totally lost when it comes to water.

My plan was to use our tap water and dilute it with distilled to lower the hardness to the minimum recommended by La Marzocco so I can avoid needing to descale. Using the test strips provided, the water mixture fell within the ranges recommended by LM for hardness, alkalinity, PH etc. However, when I punch those same values into LM's online water calculator, I get an angry red warning of "Heavy corrosion." It seems like by trying to solve for scale and hardness, I perhaps created other problems. (As an aside, I know that some folks have mentioned that the calculator is a rather limited tool, especially when pared with the imprecise testing strips LM provides with the Linea Mini. In fact, I found that if you populate the fields with the minimum values for each water quality characteristic recommended by LM, you still get the "Heavy corrosion" response.)

My goal is to put water in my machine that is going to keep it clean and healthy. Ideally, I would like to find a way to treat or soften my city's (Minneapolis) water if possible.

I know Minneapolis water has been addressed in a previous post and it was suggested that the city's water isn't bad and some softening would be all that was needed.

Help with Minneapolis MN water quality and filtration needs

It seems like our most recent water analysis tracks closely with the numbers listed in this post from 2018. I assume I should base any strategy on the numbers the city provides as I don't have testing equipment that could possibly be more accurate.

https://www2.minneapolismn.gov/media/co ... 021web.pdf

Any guidance on this would be much appreciated. I only passed my high school chemistry class by copying the student council president's homework and I really regret that right now. ¯\_(ツ)_/¯

Mike

Have you considering using R Pavlis water? I was terrible in high school chemistry as well. I have found, thanks to this forum, that R Pavlis water is a safe and easy to make water for optimum espresso machine health.

Given your numbers:
TDS 172 ppm
Total hardness 93 CaCO3 equiv ppm
Ca Hardness 92.5 CaCO3 equiv ppm
Alkalinity 59 CaCO3 equiv ppm
chloride ion 25.3 ppm
pH 9.8

You do expect limescale in a 125C (appx 1.3 bar at sea level) steam boiler. The LSI pHs at this temp comes out to 6.5, so water with a pH higher than that would tend to deposit rather than dissolve limescale. The water in your plumbing system has been treated so as to have that high pH. That high pH helps with corrosion and possible metal leaching from plumbing systems. To do boiler scale calculations you could use a pHeq value of 7.1, which better fits your water's alkalinity, and at that value you still expect light scale. (If you want to get into this, the best read by far is Jim Schulman's Insanely Long Water FAQ . )

If you want safe, chloride free, non-corrosive water that never requires descaling, then mixing your own per the R Pavlis formula would work great.

If you want to treat it with a plumbed in solution I think your best bet is a conventional (sodium exchange) softener with a carbon and particulates filter. With that amount of chloride in the water you want to keep your alkalinity high and avoid acidifying the water with a decarbonizing (hydrogen exchange, WAC resin) softener. If you wanted to be cautious about possible corrosion from plumbing in to this water you would need to use RO to remove that chloride, then remineralize.

P.S.
I agree with others that the LM water calculator is a little too simplistic. You also need to drive it carefully. When changing numbers I think you want to reload the page (so that the old warning goes away) then click the submit button with the new numbers. In your case it should have given you this:

I just noticed the topic title says "Tap + distilled" and realize that I didn't address that. When using that approach, especially when you have some chloride in the water, you want to take care to not dilute it so that your alkalinity drops below 40 - 50 mg/L. You could dilute yours with 20% distilled to get an alkalinity in the 45 mg/L neighborhood and it probably would not scale, but it would also still have about 20 mg/L chloride. if you are going to be mixing water I think It would be far better to go with something like R Pavlis here. (100 mg potasium bicarbonate per each liter of distilled or purified. Zero minerals that can cause scale and zero chloride or other potential corrosives.)

Espresso Cart - Goodbye Plumbed In

Most of the why is in the thread, but in short, no worries about any choride at all, plus its consistent and repeatable after set up with not much work. I can provide details if you choose this.

homeburrero wrote:I just noticed the topic title says "Tap + distilled" and realize that I didn't address that. When using that approach, especially when you have some chloride in the water, you want to take care to not dilute it so that your alkalinity drops below 40 - 50 mg/L. You could dilute yours with 20% distilled to get an alkalinity in the 45 mg/L neighborhood and it probably would not scale, but it would also still have about 20 mg/L chloride. if you are going to be mixing water I think It would be far better to go with something like R Pavlis here. (100 mg potasium bicarbonate per each liter of distilled or purified. Zero minerals that can cause scale and zero chloride or other potential corrosives.)

Why the concern over dropping alk below 40-50 on the tap if all else drops equally? Is that to prevent corrosion in presence of chlorides?

Thank you everyone for the replies!

I've been hesitant about mixing my own water using exclusivly distilled because I haven't been able to figure how to source it beyond buying gallon after gallon at the grocery store. But I do think i'll go the R Pavlis route in the short term while I figure out a RO / Remineralization system that will be a more permanent solution and generate less plastic waste in my recycling bins.

I don't think i've ever thought so hard about water - something I've taken for granted my entire life - before.

Thanks again everyone. I really appreciate it.

-Mike

RyanJE wrote:Why the concern over dropping alk below 40-50 on the tap if all else drops equally? Is that to prevent corrosion in presence of chlorides?

40 mg/L has for decades been recommended as a prudent minimum, and it's generally true that any chloride may be corrosive. Acidity and chloride together make the corrosion risk worse. In the case of this tapwater you have an undiluted alkalinity of 59 ppm and chloride ion of 25 ppm. Even if you only dilute down to an alkalinity of 47 ppm and chloride ion of 20 ppm the water may be slightly more corrosive than undiluted tap. The main benefit to doing that would be in easily having water that may never require descaling. In my opinion conventional softening would be a better way to get there, and of course making R Pavlis or similar would be far better.

Shinyandchrome85 wrote:I haven't been able to figure how to source it beyond buying gallon after gallon at the grocery store.

Be sure to look into self serve kiosks where you can refill large containers. You can use an inexpensive TDS conductivity meter to verify that the RO unit is maintained and water is up to par. My store (a Whole Foods) sells self-serve RO and de-ionized at the same price, and the de-ionized reliably comes out at 0 - 1 ppm on a TDS meter.

homeburrero wrote: Be sure to look into self serve kiosks where you can refill large containers. You can use an inexpensive TDS conductivity meter to verify that the RO unit is maintained and water is up to par. My store (a Whole Foods) sells self-serve RO and de-ionized at the same price, and the de-ionized reliably comes out at 0 - 1 ppm on a TDS meter.

Thanks for this tip! I was nervous about potential plastic use and this should all be eliminate that.