a Q about phospates

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JamesW said:
The person making a claim has to provide the support for their claim.
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This is an article in a trade magazine and not a scientific research paper so the author is really under no obligation to support any claims. Most of the internet is made up of various claims, some plausible, some dubious and most totally ridiculous. However, I do agree that if they wanted to be taken seriously, they should have provided more supporting evidence. But the article is not completely devoid of supporting evidence either:

A product known as zinc orthophosphate is used in drinking water systems because it adheres to metal pipes and acts as an anti-corrosion agent. So, from this we know that orthophosphate likes to cling to metals. The real interference of phosphates in chlorine generators is still somewhat theoretical. It appears that since orthophosphates attach to metals they attach to the anode and cause an interference with the flow of electrons between the anode and the cathode of the salt chlorine generator. We do know that higher levels of orthophosphate seem to cause a definite interference with the normal operation of the salt chlorine generators.
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The use of orthophosphates in water distribution systems is fairly well documented so I think that part is relevant.

www.epa.gov

Why do water systems add phosphate to drinking water? What are the health effects of drinking water containing phosphates? | US EPA

Why do water systems add phosphate to drinking water? What are the health effects of drinking water containing phosphates?
www.epa.gov www.epa.gov

Also, the above articles explain that the protection that orthophosphate supplies to pipes, besides sequestering, is really a form of mineral scale and we do know that scale inhibits the electrolytic reaction. We also know that scale comes in several flavors including calcium carbonate and calcium phosphate both of which are possible in swimming pools and most likely SWGs as well.

blog.orendatech.com

Understanding Calcium Carbonate Scale

Calcium carbonate scale is a result of water being oversaturated with calcium carbonate, as measured on the LSI. Learn more about other types of scale too.
blog.orendatech.com blog.orendatech.com

Chem Geek was mentioned:

Thanks to renowned water chemist Richard Falk, here is the formula for how much phosphate you need in your water in order to precipitate calcium phosphate scale:

PO4 = 10^[11.755 - log(CaH) - 2log(t) - (0.65 * pH)]

The temperature "t" is in Celsius.
So for 375 ppm CH, 7.5 pH and 80ºF (26.67ºC) we have
10^[11.755 - log(375) - 2log(26.67) - (0.65 * 7.5)] = 28.44 ppm = 28,440 ppb phosphate
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Given the PH near the SWG plates is higher than in the body water and using a higher CH level of 600 ppm, pH 8, and a water temp of 100F, conditions one might find in a spa, the PO4 required drops to 4.2 ppm, a little lower than what my pool experienced. Also, the Orinda article mentions that calcium phosphate is harder than calcium carbonate:

On the Moh's 1-10 scale of mineral hardness, calcium phosphate is a 5, whereas calcium carbonate is just a 3. If you have calcium phosphate scale, it can be extremely difficult to remove and sometimes justifies replacing equipment entirely.
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So it seems plausible to me that there could be a direct relationship.
 
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You’ll never get at the underlying chemistry by just looking at SWGs in swimming pools. For one, there is just too much variability in pool water conditions to make clear comparisons. Second, even if you could show some underperformance versus phosphate concentrations what you’ve accomplished is an empirical experiment that is a posteriori knowledge. A true scientific experiment uses a priori knowledge to build up a hypothesis and then uses controlled experiments to try to falsify that hypothesis. One way to think of it is like taking aspirin -

“I have a headache … I took aspirin … my headache got better … aspirin is good for headaches.”

While that empirical test proved aspirin is a good for a headache, it tells you nothing about how the aspirin works inside the human body to reduce the pain and fix the headache. The information is still useful, but you don’t learn a lot and if you give someone aspirin with a bleeding disorder you could kill them. You’ve gained some useful knowledge but it’s incomplete at best and very dangerous at worst.

SWG and phosphates are the same way - you can get a lot of empirical evidence that indicates phosphates could screw up an SWG cell, but that’s all you ever find and you won’t really be able to fix the situation. The only way to go deeper is to take the experiment back to a lab where you can control the materials in question and make much better observations of the chemistry going on. Then, once you understand the underlying chemical mechanism of action, you can start making better predictions about what will happen in a pool.

One hypothesis that I have postulated but don't have the equipment to prove is that phosphate ([PO4]-) could be reduced to phosphite ([HPO3]2−). Phosphites are very well know chlorine scavengers and can reduce chlorine to chloride very easily. If the cathode can produce sufficient amounts of phosphite then that would reduce an equivalent amount of chlorine back to chloride. You wouldn't see any change in current, just reduced chlorine output. If it were scale (calcium phosphate) causing the problem, then you would see a reduction in chlorine AND a reduced amount of current.

Give me a high tech chemistry lab and I can prove myself wrong ...
 
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mas985 said:
This is an article in a trade magazine and not a scientific research paper so the author is really under no obligation to support any claims.
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If the person is an Industry Professional making scientific claims, then we should be able to expect them to have some sort of legitimate basis and proof for their claims.

Speculation and conjecture cannot legally be presented as confirmed facts.

You can't just make up whatever nonsense you want and claim it to be accurate and truthful information.
 
mas985 said:
Start a GoFundMe:

Lab Space | UACI

www.uaci.com www.uaci.com
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My oldest graduates from Highschool in a few weeks and will be a Wildcat in the fall!! Maybe he can sneak me onto campus and I can use the lab space when security is on their coffee break 🤔
 
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Oh, come on, man, you can’t possibly believe that any school on the face of the Earth can compare to ASU.

Seriously, it is the number one school that has ever existed.

Their admittance rate is 1 in 1 million.

For every 1 Million applications they receive, they only admit one person.

ASU has produced more Nobel laureates than all of the other schools combined.

ASU has produced more Supreme Court Justices than all of the other schools combined.

ASU has produced more Billionaires than all of the other schools combined.

ASU graduates are Champions in every field.

They are the best scholars, athletes and the best human beings.

These are indisputable facts.

If an ASU graduate told me that phosphates caused SWGs to produce less chlorine, I would instantly believe them on their word alone due to their credibility.
 
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mas985 said:
Scientific discoveries often start with a hypothesis.

I believe I have read other references to this but unfortunately I do not have the links. However, I believe this was discussed in one or both of the links I posted above.

I think it is plausible and even thought of an experiment to prove it. However, it might be something that accumulates over time so a short term experiment may not reveal anything.
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To be fair, without statistical analysis you can't claim it to be true. Hypotheticals are just that for a reason. If someone did proper experiments (which seems pretty possible) it'd be different.
 
Antlo said:
To be fair, without statistical analysis you can't claim it to be true. Hypotheticals are just that for a reason. If someone did proper experiments (which seems pretty possible) it'd be different.
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Did anyone in this forum or in the original article actually make the claim that it was true?
 
At the level of 500 ppb there will be a definite interference with salt chlorine generators to produce enough free available chlorine (FAC). - Terry Arko.

www.poolmagazine.com

The Basics on Phosphates in Pools

Phosphates Defined Phosphates are biological building blocks that are formed when phosphoric acid comes in contact with certain metals. Most of the natural sources are found in rivers, lakes and […]
www.poolmagazine.com www.poolmagazine.com
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That is a different article than what I had posted which is what I assumed the comment was about:

Failing Salt Generators: The Phosphate Connection

When a salt chlorine generator begins to fail it will not produce sufficient free chlorine to keep up with demand. One possible cause is the presence of phosphates in the pool water.
www.aquamagazine.com www.aquamagazine.com

In this article, it is a bit softer sell.
 
mas985 said:
That is a different article than what I had posted which is what I assumed the comment was about:

Failing Salt Generators: The Phosphate Connection

When a salt chlorine generator begins to fail it will not produce sufficient free chlorine to keep up with demand. One possible cause is the presence of phosphates in the pool water.
www.aquamagazine.com www.aquamagazine.com

In this article, it is a bit softer sell.
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Same author.

They clearly say that phosphates interfere with production.

When levels of phosphate exceed 500 ppb the unit can cease to produce enough free available chlorine to keep up with demand.

Most manufacturers of salt chlorine generators will confirm that when there is a problem with production of free available chlorine, a phosphate test is recommended.

If the phosphate levels are near or over 500 ppb, a phosphate removal treatment is advised to help the salt chlorine generator function properly.

Orthophosphate will not only interfere with salt generators, it can also cause excessive algae blooms to occur in both traditional and salt pools as well.
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But in the original article, it also has this statement:

So, from this we know that orthophosphate likes to cling to metals. The real interference of phosphates in chlorine generators is still somewhat theoretical.
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Yes, the wrong term but it is a bit of a soft pedal in my mind.

The more I read both articles, the more I think he is actually talking about Calcium Phosphate. I may email him to get clarity.
 
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