Muriatic vs Sulphuric Acid

[RTeen]

I have read the few forum posts regarding the muriatic vs sulphuric acid usage in a pool with a salt water chlorine generator. Even though there has been some comments I don’t think it is looked into as deeply as other chemical components on this site.

The contractor who built my pool insists that I use a liquid pH reducer that is sulphuric acid based connected to my dosing pump otherwise my salt water chlorine generator would fall out of warranty. Supposedly muriatic acid will damage the cell plates. I checked with other chemical suppliers in the area they also seem to lean towards sulphuric acid. It is kind of an urban legend around here. But I am sure it is not about what they have in stock because they are all well stocked with both sulphuric acid and muriatic acid, and they will be happy to sell you whatever you ask.

I understand the sulphate residue issue with the sulphuric acid. If we put that aside for a moment, is there really some science behind the usage of sulphuric acid in order to avoid cell damage or is this complete horse poop?

Thanks

 

[Kellyp]

TFP recommends muriatic for reducing PH. Most pool maintenance companies here in the U.S. also use muriatic for PH control.

Sulfuric acid is stronger and has more health risks.

 

[RTeen]

TFP recommends muriatic for reducing PH. Most pool maintenance companies here in the U.S. also use muriatic for PH control.

Sulfuric acid is stronger and has more health risks.

I am sure it does. But I want to hear more about the science behind the chlorinator cell damage if there is indeed one. I am not planning to accept blindly what anyone says including this site.

 

[Kellyp]

Of course not, and you shouldn't. I am not versed in what it might do or not to the cell. Just pointing out that many if not most people here us muriatic without issue to salt cells.

I'm sure one of our science guys will weigh in here.

 

[HermanTX]

I am sure it does. But I want to hear more about the science behind the chlorinator cell damage if there is indeed one. I am not planning to accept blindly what anyone says including this site.

There is a wide assortment of information on the website. Go to the bottoms of the page and see the TFP WIKI section.

Acid - Further Reading

www.troublefreepool.com

 

[gingrbredman]

I am not planning to accept blindly what anyone says including this site.

You should not blindly accept any recommendations, but there is so much information here about PH management, and simply put, liquid Muriatic acid is the recommended product. The TFP methods are based in science and tried and tested by thousands, and not always for the masses who are not quite ready for it.

This site is not like the Internet where free debate of off TFP protocols are discussed and bantered about. This forum is about education and discussion of the TFP methods, and wild theories about different products that do not fall within these methods usually get moved quickly. The site is not about having to prove anything to anyone, or convince anyone they are wrong or right. It really is quite simple, for PH reduction, liquid muriatic acid is the recommended chemical.

For the impact of muriatic acid on salt cell plates, there is also a lot of great information here regarding this, @HermanTX pointed to just one, but the search function will reveal so much more!

 

[RTeen]

You should not blindly accept any recommendations, but there is so much information here about PH management, and simply put, liquid Muriatic acid is the recommended product. The TFP methods are based in science and tried and tested by thousands, and not always for the masses who are not quite ready for it.

This site is not like the Internet where free debate of off TFP protocols are discussed and bantered about. This forum is about education and discussion of the TFP methods, and wild theories about different products that do not fall within these methods usually get moved quickly. The site is not about having to prove anything to anyone, or convince anyone they are wrong or right. It really is quite simple, for PH reduction, liquid muriatic acid is the recommended chemical.

For the impact of muriatic acid on salt cell plates, there is also a lot of great information here regarding this, @HermanTX pointed to just one, but the search function will reveal so much more!

I am ready to listen. That’s why I am here. If you say info here is based on science just show me the science. I will decide myself. You don’t need to prove me anything. I use the search function as well and there seems to be no analysis of effects of HCl on salt plates.

 

[markayash]

@JoyfulNoise can probably explain the science side.

 

[JoyfulNoise]

All the major SWG manufacturers state explicitly in their owner and installation manuals that the use of dry acid (sodium bisulfate … very similar to sulfuric acid) voids the warranty due to catalyst damage. Sulfuric acid would be similar in its use.

I’m not going to get into the science of ruthenium catalysts, it’s far too complex a subject for the forum. Suffice it to say, you can Google search “ruthenium, sulfur, catalyst poisoning and complexes” and you’ll find a wealth of scientific literature on the subject. Put simply, sulfates form complex ligands with ruthenium and promote its oxidation to the Ru7+ oxidation state. This yields the formation of highly volatile RuO4 and ruthenium-oxygen-sulfate species all of which are highly water soluble. It is these complex processes that lead to the loss of ruthenium metal at the plate surface. Chloride does not catalyze the same reactions and so is not as damaging to the electrode surface.

If you prefer to use sulfuric acid for pH control, that’s your choice. But you will be damaging the SWG plates if you allow sulfates to build up in the water over time.

 

[JamesW]

The entire point of adding sulfuric acid or hydrochloric acid is to add hydrogen ions, which lower the pH.

Once the acid is “properly” added to the water, there is no more acid.

You don’t have acid circulating in the water at all except for the first few seconds when the acid is added.

So, the acid never touches the cell in any way.

Both add hydrogen ions.

The only difference is what comes with the hydrogen ions, either sulfate or chloride.

Chloride is intentionally added to a salt pool because that is what the SWG needs to work.

So, the idea that muriatic acid properly added is a risk to the cell is complete nonsense.