Looks like I will be upgrading to either the La Marzocco Mini or Micra here before too long. I see that there are specific water requirements which makes sense. I cannot get the brands that they advise near me though. They said I can get 3rd wave packs. I was wondering if I can use maybe a cup or so of the Crystal Geyser from NY with mostly the distilled water? With such a small amount I can't see that doing any harm? Some of the reviews for the 3rd wave were not too positive. Any thoughts from those about the water are appreciated.

If you can't easily get one of the "non-scaling" bottled waters, or you want to explore how different waters impact the flavor in the cup, mixing your own is straightforward. Starting with distilled, RO, or RO/DI and then one or two, readily obtainable ingredients, it is easy to mix a liter or more as you need it. Lots of options in the Water sub-forum from RPavlis' suggestions and up in complexity.

Personally, I use RO/DI from a bulk machine at a local Whole Foods and 1000 ppm equivalent concentrates for "GH" and "KH". That makes it "math-free" in the morning as 20 g of concentrate in a liter total of mix is 20 ppm.

Thanks and I will have to look into that. I have access to RO water too. Where do you get those concentrates at?

I use baking soda and food-grade epsom salt. There are other choices, often available in grocery stores or wine-making supply shops. I don't know that there's a "best" agreed, even for a given roast level, burr set, and machine. The good news is that it isn't too hard to get good-tasting, non-scaling water without investing in a chemistry lab. A couple of bottles and a reasonable scale that can weigh a few grams to hundredths of a gram are enough.

I make R Pavlis water by mixing .4 gram of potassium bicarbonate with one gallon distilled water. As Jeff suggested, the water forum is loaded with water advice.

Ok, cool. I think I have that from my winemaking supplies. I will check tonight but it sounds familiar to me.