RO water TDS Level

[aqua_chem]

I also mentioned kh being the carbonic element of gH. By my tests tds and gh are similar numbers, close enough to be the same.

Correlation is not causation. The primary component of groundwater in many places is calcium carbonate, so the levels are generally equal, but this is due to stoichiometry, not definition. KH is NOT a component of GH. They are completely independent of each other.

The amount of TDS will buffer the water up down accordingly. TDS is hardness. This is Wrong.

I'm sorry, but you're simply wrong on this. TDS includes KH, but is not limited to KH. A high TDS composed of non-buffering components will not buffer water.

"There are several ways to define acids and bases, but pH and pOH only refers to hydrogen ion concentration and hydroxide ion concentration, respectively. pH and pOH are only meaningful when applied to aqueous (water-based) solution.

As I explained, this is the oversimplification that we use to explain the basics of pH to non-physical science students. It's mostly correct. You can find a billion sources stating this because they are all targeted at beginners. Every Chem 1## college class in the country teaches this, and it is retaught correctly in upper level science classes when students have a better foundation to understand the nuance. One of my professors in undergrad once described chemistry education as the art of teaching rules, then breaking them. Please reread the wikipedia article on pH as it explains it in more accurate detail. Here is another page that explains activity vs concentration. I am 100% confident on this matter.

 

[J.Mcpeak]

Correlation is not causation. The primary component of groundwater in many places is calcium carbonate, so the levels are generally equal, but this is due to stoichiometry, not definition. KH is NOT a component of GH. They are completely independent of each other.




I'm sorry, but you're simply wrong on this. TDS includes KH, but is not limited to KH. A high TDS composed of non-buffering components will not buffer water.



As I explained, this is the oversimplification that we use to explain the basics of pH to non-physical science students. It's mostly correct. You can find a billion sources stating this because they are all targeted at beginners. Every Chem 1## college class in the country teaches this, and it is retaught correctly in upper level science classes when students have a better foundation to understand the nuance. One of my professors in undergrad once described chemistry education as the art of teaching rules, then breaking them. Please reread the wikipedia article on pH as it explains it in more accurate detail. Here is another page that explains activity vs concentration. I am 100% confident on this matter.

Based on liquid tests for aquaria.

Quote 1, I understand the gh test calculates the total hardness of a water body, including kH, kh is a specific test of its carbonic elements.

This should correctly say, I up until recently understood that-

To test for magnesium and calcium a specific test for each element is required.

You can get a high gH reading and have 0 magnesium and 0 calcium. I know this to be true.

Quote 2, I said it was wrong, it's written quite plainly. Thank you for confirmation.

My last post admits that tds includes among other things gh/kh. This is why the numbers are only close. I assumed that was my rounding up and losing a decimal place. (Tests were carried out upon purchase of RO unit, that was many years ago before I really knew anything)

Quote 3, you know full well from our off air conversation I'm not even a foundation student of science, if people only give the basics, that which I use as a basis for all of my self taught studies, what can I do about that? Every source online and on the bookshelf says the same thing, I am inclined to believe it and argue-(use this word liberally) toward that end.

I am currently 100% confident but am always open to new fresh education.
I stated elsewhere, before I was a fish keeper all I knew about water is that it was wet and came in two types, hot and cold.

Edit- my previous post also states that I have more to learn. Educate me and the masses

I must be a very lucky fish keeper! I've used these principles for years.

 

[J.Mcpeak]

Predominantly a question for mark, others please feel free to interject,

If the activity of hydronium ions is very difficult to test what is the benefit of its inclusion?

While I now appreciate the difference and will try to further my understanding of it, how can I apply that to Fishkeeping water science if I can only yield an estimate. My pH test gives me an estimate which is perfectly usable.

That page (here) suggests only an estimate can be made. This would lead me back to my more basic understanding of the strange occurrence we term pH.
Quote from that page,
"We know that pure water at 25 °C has a pH of 7.00 and that the concentrations of hydronium ions and hydroxide ions are equal."

What have I missed?

I had a look at the Wikipedia page, do you fully understand all that is written there?

That's three questions.

 

[aqua_chem]

The issue arises when there is discrepancy between calibration and application. For instance, if your testing method is calibrated in a solution with ionic strength A (what TDS is affecting), and you use it to test a tank with ionic strength B, your test might be significantly different. An example of this would be a discus keeper who uses the standard calibration kits to calibrate a pH probe (which likely has a high buffer concentration and thus high ionic strength) and tries to measure the pH of his extremely soft water aquarium. Saltwater tanks may also suffer from something similar, depending on the differences between the test solutions and the tank itself. I believe that API includes different test cards for pH in salt and freshwater, likely in large part due to this difference.

 

[J.Mcpeak]

That kind of answers questions 1/2.
Yes I'm aware of the high range/low range pH solutions, liquid tests.
I did read that about the pH meters, I was put off of them because of the super acid/basic anomaly. I guess though in Fishkeeping you will never be getting these readings. If you did you would most certainly be looking at a tank full of dead stock!

That does help explain why there are two calibration solutions for the sticks. Around 4 & 8 pH.

I'm learning! What else have you got?

Question 3 and quote 1 confirmation either way?

I would like to say this isn't an argument, education isn't supposed to be easy! I must question everything.

 

[aqua_chem]

I'm not sure what your third question was. Can you restate it?

 

[J.Mcpeak]

Do you fully understand the Wikipedia link. The reason I ask you is, you can tell me how to run through the algebraic equations so that I might put them to use. I am not an (we call them) A level maths student.

I have some further questions also, these will be asked in due course.

I am going to conduct some tests with my new found knowledge and my more advanced skill set, and present my findings. I feel you are one such person who can assist and confirm my findings for the benefit of all who may read this post.

It would seem that on this particular website you are to be considered an authority on certain areas regarding science related fish study.

 

[aqua_chem]

The wiki page for pH doesn't really have the proper equations that you would use (they're under ionic strength and thermodynamic activity). The problem is that nothing we use in aquaria is accurate to really apply them right, which limits application from a quantitative perspective. Qualitatively, it's important to recognize the discrepancy for certain circumstances, but really that's only a few niche applications.

 

[J.Mcpeak]

Aqua_chem,

Is this convoluted circumvention?

If both main contributors to this thread are wrong. Teach them and all other readers what is right. You can't leave so many areas of question unresolved.
If you don't know it's no bad thing, perhaps we can all unite to find the correct results that will benefit every reader of this thread.

If the more diverse understanding of pH, as has been brought to us is of no real benefit in an aquarium environment why bring it to the table?
Over complicating what should be a simple affair really serves no purpose that I can see.
My understanding has been brought to question, left in disarray and abandoned, what was the achievement? Was anything achieved?

This is supposed to be an assistance service provided to all fish keepers, of all ages, sexes, stations and educational level.
Whoever you are whatever you do, one thing alone makes us equal.

Sorry if that sounds rough, but that's what I am thinking at this point.

 

[aqua_chem]

In a nutshell, it's because it's important to know where general rules break down so as to not apply the rule there. And to that end, I believe that the material I've linked explains where it can be a problem well enough. It was largely also for dmolavi's benefit as I thought it would be interesting for him, but he appears to have abandoned the thread before I started posting.


Also, one of my pet peeves in this hobby is that things that are "mostly true" or "usually true" are repeated ad nauseum until they become accepted fact. A more egregious example of this that used to come up all the time was the idea that a bubbler shouldn't be added to a planted gas because it offgases CO2. This is true, when CO2 is above equilibrium levels, as is the case in unplanted or CO2 injected tanks, but in non-high tech tanks, the is simply not the case. Yet, this advice often given on this forum, and demonstrates the issue above.

 

[J.Mcpeak]

Ok. I agree with co2, enough fish will make its use redundant.
I've never used co2 and have managed to achieve excellent plant growth in the instance I attempted a properly planted (well stocked) tank.

Back on point,
The "accepted" convention on pH is adequate?
I mean, it is suitable enough for the aquarium and its applied water science.

(I skipped algebra, I'm trying to skip it again!)

(Possibly I may have aggrieved dmolavi)

 

[Rare]

To the OP.. What are you using in your 3 stage RO filter?

 

[Niks76]

Carbon filter, 1 micron filter, and 24gpd TFC membrane.