homeburrero wrote:Light and Bright manual brew (6 drops calcium + 5 drops potassium in 450ml):
1.2 mEq/L CaCl2 (60 ppm as CaCO3)
0.5 mEq/L KHCO3 (25 ppm as CaCO3)

To be honest, this is exactly what I meant when I said the Lotus website said it should be 85 ppm (60ppm + 25ppm). I just assumed that meant my TDS meters should also show 85 ppm. I had no clue how to measure the conductivity like you just did.

I remade the recipe again this morning, but this time I shook up the concentrate bottles before adding the drops, and instead of squeezing until each drop came out fully, I squeezed until each drop was halfway out the dropper, waited a second for the drop to get bigger, and then dropped it into the water. After these changes, both TDS meters showed 70 ppm

So 70 ppm is quite a bit more than the ~45 ppm number I was getting before, but it is still far from 105 ppm. I measured at room temp which was right about 25 degrees Celsius.

Since both different brand TDS meters give the same reading (within 1 ppm every time) I do not think it is a calibration issue with the meters. I just ordered a titration test kit to get a more reliable reading for more clarification.

I will report back what I find out. What do you think the issue might be?

BeatTheSunUp wrote:To be honest, this is exactly what I meant when I said the Lotus website said it should be 85 ppm (60ppm + 25ppm).

That's a fairly common misunderstanding - - that the TDS ppm approximates the sum of the hardness and alkalinity as CaCO3. To illustrate why this is not at all true consider the situation of a distilled water plus exactly 50 ppm of actual CaCO3, which has a total of 50 ppm dissolved solids. It has a hardness of 50 ppm as CaCO3 and also has an alkalinity of 50 ppm as CaCO3. Adding them together would be 100 ppm, but that would be counting the same molecules twice!

BeatTheSunUp wrote:What do you think the issue might be?

Not sure what's going wrong and I don't have any Lotus drops to test myself.

BeatTheSunUp wrote:I just ordered a titration test kit

To test with that I'd recommend making a 100 ppm as CaCO3 calcium chloride sample, by adding 10 drops of calcium to 450 ml and test that for GH (total hardness).

Then make a new 100 ppm as CaCO3 potassium bicarbonate sample, by adding 20 drops of potassium to 450ml and test that for KH (total alkalinity).

You should see in the ballpark of 100 ppm as CaCO3 (5.6 °dH) for each of those.

Thanks for the recommendations on the titration test! I'll let you know how it goes after I do it.

homeburrero wrote:
Also, their claims about the effect of calcium and magnesium on taste is not at all established.

In the earlier videos, as I remember, they had claims on magnesium and calcium opposite of what most state. I think they claimed calcium supplies sweetness and magnesium creaminess and texture.

With high concentrations, what is risk of precipitation of the minerals.

Acavia wrote:In the earlier videos, as I remember, they had claims on magnesium and calcium opposite of what most state. I think they claimed calcium supplies sweetness and magnesium creaminess and texture.

Lotus Water is still doing it, mixing up calcium and magnesium roles on coffee extraction, on its site.

For example, everything I have read on coffee water is along these lines:

"Magnesium ions in water aid the extraction of sharp, fruitier flavours, calcium emphasises heavier, creamy notes - and that 'buffer' is antagonistic towards sharper, acidic notes. " https://www.coffeescience.org/how-to-ch ... or-coffee/

While Lotus water has it backwards:

"Calcium
Juicy, acidic, bright. Calcium in water recipes can help highlight the sweetness and acidity of coffees while maintaining a high degree of clarity. It's our preferred form of hardness for light roasts. While calcium does a great job of accentuating the fruit notes in coffee too much can pull in bitterness and astringency.

Magnesium
Bold and complex. If your brew is coming out too one dimensional then magnesium is sure to help with that. This mineral is useful for adding body and bringing out a wide variety of flavors in your coffee. While the variety of flavor magnesium brings is great, too much can cause coffee to taste muddy or complex to the point that no one particular flavor is easy to identify or pick out. "

https://lotuscoffeeproducts.com/pages/c ... own-recipe

I am suspicious they do this to make people reading about making their own water to not trust sites promoting do-it-yourself water.

homeburrero wrote:

To test with that I'd recommend making a 100 ppm as CaCO3 calcium chloride sample, by adding 10 drops of calcium to 450 ml and test that for GH (total hardness).

Then make a new 100 ppm as CaCO3 potassium bicarbonate sample, by adding 20 drops of potassium to 450ml and test that for KH (total alkalinity).

You should see in the ballpark of 100 ppm as CaCO3 (5.6 °dH) for each of those.

I finally received the titration test and did a stretched titration using the two 100 ppm recipes that you suggested. As it turns out, my Calcium and Potassium concentrates are the exact strength that they should be. It is the TDS meters that are "off." Neither of them measure 105ppm. the nicer of the two measures it around 78-80 ppm, while the cheaper one measures it around 72-74 ppm. At least I now know the recipe is correct and the TDS meters are off

Acavia wrote:In the earlier videos, as I remember, they had claims on magnesium and calcium opposite of what most state. I think they claimed calcium supplies sweetness and magnesium creaminess and texture.

Lance Hedrick has a YouTube video with Samo Smrke about water where they acknowledge this. Samo specifically says that the general consensus of Calcium vs. Magnesium is the opposite of Lance's blind taste test findings. But I think that's the beauty of Lotus Water. Different people will have different preferences, and Lotus makes it very easy to try different recipes

So I actually did a blind taste test of Light & Bright where I used Calcium as the hardness in one vs. Magnesium as the hardness in the other, and I actually preferred the Calcium over the Magnesium just like Lance.

Is there any way to use a TDS meter to ballpark the GH and KH of various waters assuming there is no CaC03 in them?

A very low TDS reading does tell you that your GH and KH is also low, but higher readings don't tell you much, especially for formulated waters or softened water. For example, a very hard water that has been conventionally softened will have a high TDS reading even though the GH may be very low.

You can use it as a crude sanity check on your formulated water but it will depend on the formula. With an inexpensive NaCl calibrated TDS meter, read at 25C, TWW should come out in the 150 ppm ballpark, and rpavlis (100 mg/L KHCO3) should come out in the 60 ppm ballpark.

For the claimed concentrations of Lotus drops it should be in the ballpark, but depends a little on the salt.
10 drops CaCL2 per 450 ml (100 ppm as CaCO3) should read about 130 ppm
10 drops MgCl2 per 450 ml (100 ppm as CaCO3) should read about 120 ppm
20 drops KHCO3 per 450 ml (100 ppm as CaCO3) should read about 120 ppm
20 drops NaHCO3 per 450 ml (100 ppm as CaCO3) should read about 95 ppm

(Those numbers are based on the handy Aqion calculator and assume a conductivity TDS meter calibration factor of 0.5 ppm per µS/cm )