lol, you f'er. Let's say instead of authority, I know a lot about measuring water? :)
But there's no point arguing, doesn't matter in the context of the OP's question.

If I were inclined to read the article, I might offer an interpretation of what it's really saying, but I'm not inclined at the moment. I'm hungry.

Food defuses everything!

TripleT, I see you live in Calgary, why do you have acidic water? Calgary water is very hard with a pH of of over 8. At any rate as stated once mixed with salt you'll have everything you need in the water, even if you end up with a lower pH it won't matter. People who run Ca reactors can testify running a slightly lower pH won't do any harm.

No, he is arguing against what Randy Holmes-Farley has written in that article.
Unless he can produce something that makes me believe his qualifications are better than Randy's, I stick with Randy.

Tell ya what. You calibrate your Apex with 4 and 7 solution, make up some RO water, shake it a bit to off gas any CO2 and measure the pH. Tell me what you get. :)

I don't even know what an apex is.
As for pH, I've not checked pH of any of my tanks or any of my other breeding waters in probably 20 yrs.
I find it odd though that you don't read the article by Randy so that you CAN reply to what he states.
You still haven't produced anything I believe in so we will have to agree to disagree.
We've both stated our points and readers will believe one or the other, regardless of what we are posting.

I'll read it when I have time, and offer my interpretation. Apex is this weird little device everyone but you seems to have, it controls aquariums and has a pH probe.
But here's the basics. You stated, from your interpretation, that pH measures salts. It does not. It measures the molar concentration of H ions in a solution. Pure water has a theoretical balance of H and OH ions, giving a pH value of 7. Given the experiment above, you will find that your pH meter of choice will give you very very close to that value when you measure it. Within the error scale of the device you're using. I've used high end lab equipment to perform this test, and received an accurate measure of 7.0.
Now Randy is a smart guy, way smarter than me on my good days. So I'm sure there is some truth to whatever he's saying, and I will read it, honest, but I don't think he's saying what you think he's saying. If I get bored, I'll even go talk to him about it :)
You do further state "within hobbyist's capabilities", so slightly moving the goal posts, so I can't address both items. My initial statement that pH measures salts being wrong stills stands.

So here's the take-away. For hobbyist purposes, you almost never have to worry about pH. The salt mix takes care of putting it where it needs to be. If you have a pH meter and just want to test stuff, whether your tank, tap water, or glass of orange juice, your meter, being a cheaper hobbyist unit, will still give very accurate results for your purposes. SW is about 8. Tap water will be about 6.7 - 7.2. Orange juice is high 5's, as I recall.
In the end it doesn't matter, which is why I'm not terribly concerned with reading more stuff. But I will try to fit it in :)

Ok, light reading, we want to address this statement, I presume -

"2. The pH of highly purified water is not accurately measured by test kits, or by pH meters. There are several different reasons for this, including the fact that highly purified water has very little buffering capacity, so its pH is easily changed. Even the acidity or basicity of a pH test kit’s indicator dye is enough to alter pure water’s measured pH. As for pH meters, the probes themselves do not function well in the very low ionic strength of pure freshwater, and trace impurities on them can swing the pH around quite a bit. "

What Randy is saying here is that measuring the H concentration is difficult, not because salts (buffers) are there or not, but due to lack of buffering capacity within highly pure water. With this lack of buffering, the solution is highly variable in pH due to it's environment. CO2 contributes carbonic acid to the solution altering it's pH (lowering it). Water with more buffering capacity is more resistant to these environmental changes. Which is why in my example above I say to off gas CO2 before measuring. This will give an accurate enough measure of the sample.
What Randy is NOT saying here is that pH measures salts. Also keep in mind that moving from pH of 6.9 to 6.7 is a big number mathematically, hence "quite a bit" . But for our purposes, it's minimal.

I think you've just read more into this than you needed to, and your initial claim re: measuring salts in inaccurate. pH is Latin for "weight of Hydrogen" and as described, measures Hydrogen.

No, I didn't state that pH measures salts, I stated that the pH reading was dependent on the salts being present. As the RO/DI process removes the salts, without the salts there is no buffering to assist a reading. I didn't state this last part but thought it only necessary to state the salts were needed to get the accurate reading.
The LACK of buffering capacity is BECAUSE the salts are no longer there in the treated water.
I never said that Randy was saying pH measures salts either.
I also know about the gassing of CO2.
As for why I don't have pH measurement tools and other automated devices, I started the hobby many many years ago when these things were not available to us here in the hobby, and as I never found a need for it, I never bothered wasting my money on it as things worked out fine without.
I still have no need of these devices in any of my tanks even though I now only have seahorses.
At my age and in my condition I've had to drop all the reef tanks and stuck with my newer passion, being physically unable to keep up everything.
Please show me where I said that "measuring salts is inaccurate".
Possibly you misread what I actually said?

As i was reading this, Brad I'm glad you read the article and replied because I didn't want to type it oht on my phone. :lol:

pH is probably the most misinterpreted parameter in our tanks.