Clarification of hardness terminology please.
In Jim Schulman's Insanely Long Water FAQ , page 12, Taste Test, references are made to "hardness and alkalinity".
Is "hardness" the same as "Total Hardness" and is "alkalinity" the same as "Calcium Hardness"?
The reason I ask is I was lucky enough to score an Ashland Chemicals test kit used for cooling tower water testing and that is what it references.
I've gone to the effort of installing an Everpure Claris system so I want to make sure I have everything setup properly. Using the the test kit here are my readings:
City Water-
125-130 ppm Total hardness
100 ppm Calcium hardness
7.2 PH (measured using a pool test kit)

Previous to the Everpure Claris I was using RO water with a calcite filter:
6 ppm Total hardness
2 ppm Calcium hardness
6.8 PH (6.8 is as low as the pool test kit goes)

Now with the Everpure Claris set at bypass level 4:
60 ppm Total hardness
40 ppm Calcium hardness
6.8 PH
The hardness titrant I was using was 10 ppm per drop so the readings are really 50-60 and 30-40 ppm.

Drained about .75 liters from the boiler and tested that:
70 ppm Total hardness
40 ppm Calcium hardness
7.2 PH
I used the machine for a few weeks on straight city water before I installed the Claris filter and I am guessing the increase in PH may be due to slight scale build up that is being removed (hopefully) by the slightly acidic 6.8 PH water (or maybe more acidic since my pool test kit only goes to 6.. What are your thoughts?

If my assumptions of the terms hardness and alkalinity are correct (with regards to the test kit I am using) then it looks like scaling will not be an issue at bypass level 4. This looks fairly close to the "RO and Tap Water" of Jim's Taste Test on page 12.
Am I correct?
I have increased it now to level 5 and will check it again next weekend.
Your comments please.


...split from Determining Water Hardness (Anyone know German Hardness) by moderator...

Hardness is the presence of ++ cations and -- anions in water; since these dissolve at low temperatures and precipate out at high temperatures to form scale. Alkalinity refers to the -- anions in water, bicarbonates only in uncontaminated water. Total hardness is the same as calcium hardness and refers to the ++ cations, calcium and magnesium in uncontaminated water.

German inspired kits use "GH" for calcium and "KH" for alkalinity. This may answer your question and explain your results.

Hardness is the presence of ++ cations and -- anions in water; since these dissolve at low temperatures and precipate out at high temperatures to form scale. Alkalinity refers to the -- anions in water, bicarbonates only in uncontaminated water. Total hardness is the same as calcium hardness and refers to the ++ cations, calcium and magnesium in uncontaminated water.

German inspired kits use "GH" for calcium and "KH" for alkalinity. This may answer your question and explain your results.

Hi Jim, thanks for your response.
I'm a little thick and still not clear after reading your answer. I'm trying to understand if my test kit which refers to Total hardness and Calcium hardness is the same as your references to hardness and alkalinity and which is which? Is my kit doing alkalinity?

There is no distinction between total hardness and calcium hardness. One is a translation of the German Gesamt Haerte, which is calcium hardness. I was assuming your kit measures GH and KH. Your results, based on this interpretation, are compatible with what Nicholas got with the Claris.

If you didn't measure GH and KH, I have no clue what your results mean.

Neutral water is 90 mg/L calcium harndess and 50 mg/L alkalinity. Non scaling water is below 50 mg/L calcium and alkalinity, or various trade offs shown on the table. The Claris basically gets you water that won't cause scale problems for many years and the best taste subject to that.

My kit does two separate tests. One is called Total hardness and the other is called Calcium hardness. I assumed one of them was the same as alkalinity, hence my confusion. So I guess that alkalinity is a totally different test that I don't have. Is Calcium hardness all I need to monitor or is it important to know alkalinity as well?

I think I have found part of my answer by re-reading Nicholas' thread on the Everpure
Claris.

I installed the Claris system and tested it with a rudimentary TDS meter and a GH ('general'/calcium hardness) and KH (carbonate hardness a.k.a. alkalinity) test.

So according to this carbonate hardness is the test for alkalinity. I will have to get one of these.

Am I right in assuming that my Total hardness test is the same as a TDS meter?

I'm glad you are taking somebody's word for it; it's not like I know anything about this stuff

TDS readouts are calibrated to calcium carbonate equivalents. So if there is nothing but calcium and carbonate in the water, it will read the same. If there is the lighter magnesium or sodium in the water, the TDS reading will be higher than the calcium hardness. You can figure that for a system like the Claris, if you know the proportion of TDS to hardness, the action of the filter will not affect that ratio. This means you can monitor the filter's action using TDS if you have an initial reading of both TDS and hardness.

It's not that I can't take your word for it Jim it's that I have trouble understanding all these big words. I get confused real easy. I see now that TDS (total dissolved solids) and Total Hardness are different. Thanks for your help and bearing with me.