White flakes in pool from SWG / Phosphates : YouTube Video

[Parabolic]

I would really like to know the exact cause of the white flakes that are produced by the SWG. I have 40 salt pools on my route and only 2 (this year) got some of the flakes. Why do some pools with SWG produce them and other not? And I do a very good job of keeping the water LSI balanced. I know the thing on TFP is CSI but the industry standard is LSI so I just use that. Even the Taylor wheel is LSI. So I'd rather not go down that road with this discussion at this point because they are fairly similar ways to determine good balance. I use a couple of apps these days that help me with LSI, the one from the National Plaster Council, and Orenda's.

Anyway, I have pools with similar balance(including Phosphate level) that don't have the white flakes.

Then I came across a video by a guy recently where he says that white flakes are caused by Phosphates. I really can't see how that can be. I'm pretty sure this YouTube poster got banned from here a long time ago. I do know that SOME of his pool videos are full of misinformation. And his most recent video saying that Phosphates cause the white flakes is suspect. He seems to infer that there are different types of white flakes.

Also, I don't think there are different types of white flakes. I personally think the flakes are calcium removed from the cell's plates during the reverse cycle.

I have asked both Pentair and Jandy reps. They have never heard of phosphates being the cause of white flakes. Both Pentair and Jandy however have said that high phosphates can be a cause of low chlorine production from a SWG, but not white flakes.
Here is an article to what they are talking about: Failing Salt Generators: The Phosphate Connection - AQUA Magazine

I posted a comment on this recent YouTube video of this guy challenging this assumption, but for some reason he does not like to be challenged and he pretty much immediately deleted, or blocked, my comments and now no comments that I post to his video are visible to the public. So I guess he blocked me. I was just commenting that his video was too vague and that just saying to add phosphate remover for 2 month period is misinformation without at least showing the complete balance of the pool. And the ending balance once the flakes stopped.

I would post a link to his video but not sure if I should. If you search YouTube for "How to Get Rid of the White Flakes in your Pool Caused by Your Salt System (SWG)" , this is the title of the video and you should be able to find it.

 

[Parabolic]

Re: White flakes in pool from SWG : YouTube Video

In the article I post a link to above it says this...

[FONT=&quot]"The phosphate connection[/FONT]
[FONT=&quot]So, what is going on when phosphate levels climb in a salt pool? We need to look to the industrial uses of orthophosphate in water treatment. First of all it is important to understand that orthophosphate is the detrimental form of phosphate that exists in water. 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.[/FONT]
[FONT=&quot]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."

So is it possible that the white flakes could be a product of what they discuss above?[/FONT]

 

[JoyfulNoise]

Phosphate scaling is not really possible unless the pH gets very (which it can inside an SWG cell) AND BOTH the CH and phosphates are very high. You’d need CH levels well over 1000ppm and phosphate levels at 50,000ppb or more to see scaling. It’s really highly unlikely.

I’m not going to go down the road of answering questions about other people’s beliefs or why some random YouTube clown says this or that. It’s not productive.

The science of scaling is well established in the literature and there are three types of scale you will run into - calcium carbonate scale, calcium sulfate (gypsum) scale and calcium phosphate (appetite) scale. Of the three, the most common form of scale from an SWG is calcium carbonate scale. To determine what scale types you are dealing with, there is a simple test -

Capture and collect some scale. Add a few drops of dilute (2:1 distilled water:MA) muriatic acid to it. If it fizzles like alka seltzer, then it’s calcium carbonate. If does not fizzle but very slowly dissolves (within a few minutes), then it’s calcium sulfate scale. If it does not dissolve at all, then it’s calcium phosphate scale.

Figure out what scale type you are dealing with and then list all of the chemicals those pools are seeing (especially anything the homeowner might be adding without telling you) and then we can diagnose the problem.

 

[Parabolic]

Phosphate scaling is not really possible unless the pH gets very HIGH (which it can inside an SWG cell) AND BOTH the CH and phosphates are very high. You’d need CH levels well over 1000ppm and phosphate levels at 50,000ppb or more to see scaling. It’s really highly unlikely.

SNIP

The science of scaling is well established in the literature and there are three types of scale you will run into - calcium carbonate scale, calcium sulfate (gypsum) scale and calcium phosphate (appetite) scale. Of the three, the most common form of scale from an SWG is calcium carbonate scale. To determine what scale types you are dealing with, there is a simple test -

Capture and collect some scale. Add a few drops of dilute (2:1 distilled water:MA) muriatic acid to it. If it fizzles like alka seltzer, then it’s calcium carbonate. If does not fizzle but very slowly dissolves (within a few minutes), then it’s calcium sulfate scale. If it does not dissolve at all, then it’s calcium phosphate scale.

Figure out what scale type you are dealing with... SNIP

Thanks for your insight.

Would you always consider those white flakes to be "scaling" of some sort?

I hopefully edited your post above correctly. I assume you meant to put High in there, yes?

I have done the acid test many times over the years and it always Fizzles like Alka Seltzer, so always assumed Calcium Carbonate. But I'm using pro strength Hydrochloric and Muriatic Acids, I think off the top my head like 32%. Are you saying 2:1 with what percentage of acid, or do you think it matters?

Have you ever heard of a SWG producing visible white stuff consisting of all three types of calcium you mention?

And the highest calcium I have in any of my pools is 700, and only in 2, both of them being the ones with the flaking. That is why I don't think that guy on YouTube is giving out the correct info. I think the flakes are more related to the calcium level, but then again I could be wrong. Both those pools have a phosphate level of about 300. But I've got other SWG pools with a phosphate level of 300 and no flakes, but they have lower calcium.

I wish some scientist would do a study on this an figure out why some pools do and some don't get white flakes.

 

[JoyfulNoise]

Thanks for your insight.

Would you always consider those white flakes to be "scaling" of some sort?

Yes. White flakes from an SWG are almost always scale. What else could the white flakes be?

I hopefully edited your post above correctly. I assume you meant to put High in there, yes?

Yes. Inside the SWG cell, when it is generating chlorine, the pH increases strongly due to the formation of hydroxide ions. The pH increase from the chlorine generation process will eventually be compensated for by all of the acidic chemical reactions caused by chlorine oxidation and disinfection, as well as the formation of hypochlorous acid from the dissolution of chlorine gas. But, in an instantaneous sense, the pH inside the cell is high. It can go as high as 10 to 11. This is why salt cells scale up - because the water that flows through them almost always has appreciable amounts of calcium and carbonates in it.

I have done the acid test many times over the years and it always Fizzles like Alka Seltzer, so always assumed Calcium Carbonate. But I'm using pro strength Hydrochloric and Muriatic Acids, I think off the top my head like 32%. Are you saying 2:1 with what percentage of acid, or do you think it matters?

My suggestion was to simply use some diluted MA (20 Baume or 31.45%) to make the test safe to perform with fewer fumes. Full strength MA is not fun to play with outside of a fume hood.

Have you ever heard of a SWG producing visible white stuff consisting of all three types of calcium you mention?

It is possible to get all three scaling types if all three anions are present in the water (carbonate, sulfate and phosphate).

And the highest calcium I have in any of my pools is 700, and only in 2, both of them being the ones with the flaking. That is why I don't think that guy on YouTube is giving out the correct info. I think the flakes are more related to the calcium level, but then again I could be wrong. Both those pools have a phosphate level of about 300. But I've got other SWG pools with a phosphate level of 300 and no flakes, but they have lower calcium.

I wish some scientist would do a study on this an figure out why some pools do and some don't get white flakes.

If you’d like to read a short, 2 page primer on the chemistry of calcium scale, this technical bulletin from Dow Chemical is interesting - http://msdssearch.dow.com/PublishedLiteratureDOWCOM/dh_0060/0901b803800602b8.pdf?filepath=/609-02023.pdf&fromPage=GetDo

It’s not just the calcium ions that matter, it’s BOTH the concentration of the cation (calcium) and the concentration of the anion (carbonate, sulfate and/or phosphate) that matter. You need enough of both chemical species to exceed the solubility product of the resulting scale compound. So, if water has high CH, then one can keep the carbonate anion levels lower (as measured by TA) to compensate. In my pool I have had CH levels as high as 1500ppm but no scale...why? Because of I keep my TA at 50ppm (with a CYA of 90ppm and borates at 50ppm), then my carbonate level is so low that’s it doesn’t matter. But here’s another interesting fact - I have gotten sulfate scaling from my SWG cell...why? Because I had my pool tiles cleaned by kierserite blasting (kierserite is magnesium sulfate) and that added enough sulfate to my water to cause scaling (white flakes). The flakes, when tested against diluted MA, would not fizz but very slowly dissolve. If they were calcium carbonate scale, then they would have fizzed like crazy. So, as you can see, concentrations matter a lot.

It not usually hard to figure out why scaling occurs. In those pools that have scaling from the cell, even if the bulk pool water is “balanced” according to the LSI (or CSI, doesn’t really matter which you prefer), the water may not be balanced inside the cell. Thus, if the TA is a bit too high and the CH is on the high side, scaling is much more likely. Also, scaling is far more likely in a cell that is run at 100% or near that output than a cell that is run at lower output but for a longer period of the day. One way to compensate for pH rise inside the cell is to add borates to the pool water. Borates act as a high pH buffer and have their strongest buffer capacity as the pH nears 9. So, if enough borates are present, the pH of the water inside the cell won’t go much above 9.

 

[Parabolic]

Thanks for your input. Very informative. So I guess the calcium type could be most related to the fill water. Your instance of tile cleaning is rare as to introduce calcium sulfate into the water it would seem.

I'm no chemist but it sounds from reading that article that phosphate scaling might be possible from a SWG, but then it would not dissolve with the acid test. Over the years I have not always tested the flakes. But every time I have they have dissolved like Alka-Seltzer.