Preventing scale with Profitec Pro 300 - Page 2

Water analysis, treatment, and mineral recipes for optimum taste and equipment health.
dannyboy2233 (original poster)

#11: Post by dannyboy2233 (original poster) »

vibrant_cashew wrote:Did you end up finding a source of cheap RO or distilled water in the Cambridge area? I'm also in the same boat as you and have yet to find a preferred source.
Hello fellow Cambridgian! Unfortunately, the best option I've found is buying purified water by the gallon from Target ($0.97/gallon). They mention RO is "one of the processes" used for purification so I doubt it's true RO water, but I'm sure it's good enough for my purposes. I asked on Reddit about this as well and got some understandably snarky responses, but nothing too useful. You might have some luck asking someone who works in a biomedical lab to fill some jugs with RO water, but I haven't tried that yet.

Let me know if you discover the silver bullet!

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homeburrero
Team HB

#12: Post by homeburrero »

dannyboy2233 wrote:They mention RO is "one of the processes" used for purification so I doubt it's true RO water, but I'm sure it's good enough for my purposes.
As long as the label on the bottle says 'purified water' and it does NOT indicate that it's with minerals added, the US FDA labeling regulations (21CFR 165.110 iv) assure that bottled water with that label is highly purified by processes that may include RO, deionization, distillation down to very pure levels that would read only 0 - 2 ppm on a conductivity TDS meter. Most likely it has been produced by a reverse osmosis followed by deionization by a mixed bed ion exchange resin. The same reg applies if it's bottled and labelled deionized or demineralized water.

In many places you can find water dispensers that have lower prices and allow you to re-use containers. The dispenser is essentially an RO system using local tap water, typically with UV sterilization and sometimes offering water that is further purified by deionization. They aren't subject to that same label regulation but if you can find one that sells RO, or better yet, deionized, that can be your most economical and low waste option. The RO from these machines is sometimes iffy, but you can double check it with a cheap conductivity/TDS meter. The deionized at my grocery store sells at the same price as their RO (39 cents per gallon) and is reliably less than a couple ppm. My store also sells 'alkaline' remineralized water at a higher price, but you don't want that for coffee machine use.

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dannyboy2233 (original poster)

#13: Post by dannyboy2233 (original poster) » replying to homeburrero »

Thanks for the info! That's reassuring. To your second point: I've spent quite a while trying to find a local grocery store that has one of these deionized/RO water taps, but I've been unsuccessful so far. Even the Whole Foods don't have it, at least not within a 10-ish mile radius of my apartment.