Remineralization Cartridges: Thoughts?

[Aquattro]

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.

[rayjay]

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?

[Aquattro]

Originally Posted by rayjay

because the pH reading is going to be dependent on salts in the water...

This is what I'm going on, and yes, perhaps I misunderstood your intent. However, as stated, it's incorrect. pH is not dependent on salts, although it is affected by salts. This is the point I wanted to clarify.

I think we're possibly arguing the same thing, from different sides. Yes, pH is affected, indirectly, by various salts which are providing buffering. But, that does not mean you can't accurately test, it means the value is more unstable due to outside factors like temp, CO2, etc.
In the end, yes, you can measure, but the value may not be what you expect. That doesn't mean it's wrong. It simply means the solution has shifted due to external influence.
I also agree that this is pointless, as I think pH in this hobby is a useless measure of anything, and I haven't run a pH meter in more years than I can recall.

Does OP need a remineralization thingy? No, he doesn't

[TripleT]

Thanks Guys!

My head hurts after reading all those papers on RO water

I'm actually 50km north of Calgary, in Crossfield. I understand that our water source is from the Red Deer River. If that helps any one...

Good discusion, puts what I've read into perspective.

I put Calgary down, to stop questions as to where Crossfield is.

[Aquattro]

Like I said, unless your water is coming from beneath a volcano or some other weird source, you're fine Just add salt, roughly to manufacturer's specs, and pH will be good.