Blending tap water and distilled water - Page 2

Water analysis, treatment, and mineral recipes for optimum taste and equipment health.
Al deHyde

#11: Post by Al deHyde »

It should be pointed out that TDS meters only measure conductivity (or resistivity) and then calculate a (artificial) number (TDS). This value provides no indication of what specific dissolved substances are causing the water to conduct: electrolytes. Likely lots of stuff.

Na+, K+ conduct and can give you high readings but do not cause scale. Ca++ and Mg++ also can cause high readings but will cause scale above a certain (small concentration). TDS meters are especially worthless when trying to determine 'hardness.'

When using ion-exchange methods (converting Ca++, Mg++ to Na+), the TDS usually increases (because Na+ slightly more conductive) even though the total hardness is zero (less than 2 ppm).

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Team HB

#12: Post by homeburrero »

Good points about TDS meters. They do have some uses, however.

1. They can check purified water. For example on a ZeroWater system you expect near zero readings. At around 6 ppm you know it's time to replace the filter.
2. Low readings do indicate low minerals. If you get 30 ppm on a TDS meter you can bet your hardness is below roughly 30 ppm. Low numbers can confirm that a remineralization filter is not doing much for you.
3. When blending tap and RO with a bypass, if you know the tap water's TDS and know the key mineral levels, you can use the TDS of the blended water divided by the tap TDS as a factor to estimate things like hardness, alkalinity, chloride, etc. For example if the tap water reads 300 ppm TDS, and has a GH:KH of 100:50 mg/L and a chloride of 100 mg/L, then if you blend it down to a TDS reading about of 150, you have an expectation that the minerals are reduced by about half, leaving you with GH:KH in the ballpark of 50:25 and chloride around 50 mg/L. (This is an example of a tap water that's a bad candidate for bypass blending.) You do need to take care to measure the tap water and the final water at the same temperature.
nínádiishʼnahgo gohwééh náshdlį́į́h

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#13: Post by slipchuck »

After using bottled spring water for years I decided to get a TDS meter to check it.... it had the same hardness as my tap water! Over 250ppm. Now I mix the spring water Approx 1:1 with distilled water to get it between 80-110 ppm. Not sure if it makes espresso taste better but it will prolong the life of my espresso machine

“There is nobody you can’t learn to like once you’ve heard their story.”

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#14: Post by Radio.YYZ » replying to slipchuck »

TDS meter doesnt give you level of hardness of water, look for city report on water for that! Or you can bypass it all and make your own water!
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#15: Post by BuckleyT »

Regarding buying distilled or other water in plastic jugs: am I the only one who can taste plastic in the water? No one else in my home or acquaintances seems to taste it. Doesn't matter so much what kind of plastic, although polyethylene is much stronger tasting than polypropylene. Cannot taste the plastic if it is RO from Zerowater.

There is still an off taste after it is boiled, compared to tap, zerowater or water from glass jugs. I cannot taste the difference in a brew, but I just am not comfortable putting it in my machine/body.

I also use a concoction of three different solutions to dope RO. I made them so long ago that I forget what I decided on back then. When they run out, I will try the Pavlis recipe. I have some ampules of Global Custom Water lying around, if anyone wants to buy a few small samples for comparison.


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#16: Post by spressomon »

Glass carboys are still available. Check your local brewer's supply.
No Espresso = Depresso


#17: Post by MCALheaven »

I prefer Concentrace mineral drops added to home-distilled water in glass jars. Easy to control since 1 drop from the bottle equals roughly 10ppm TDS. Yes, it contains some magnesium and calcium but it makes delicious mineral water for those with sensitive tastes. For the espresso machine I keep it down to 50-60ppm TDS.