Muriatic acid color and product purity?

[JoyfulNoise]

I have a lingering question that I have not found a satisfactory answer to. I have noticed that, depending on where I get my MA from, it can be varying shades of yellow. If I buy the stuff from Leslie's Pool Store, it is often a very bright yellow. The first time I got it, I thought they put a colorant into it for safety purposes. If I buy the refillable HASA stuff from e-Konomy Pools (local Tucson shop), it is a very pale/straw-yellow. If I splurge and waste...um I mean, spend money at Patio Pools, the MA is crystal clear (same is true about MA from Ace Hardware). From my research lab days, we bought reagent-grade HCl and it was also totally clear. All of it is marked as 20 Baume, 31.45% HCl.

I also know that the manufacturing process for making HCl does contain (or should contain) a step for iron removal as Fe-salts are a known contaminant from the manufacturing process. So, does the yellow color of the HCl indicate a poorer quality material with possible iron contamination?

 

[JamesW]

The color can come from chlorine Cl₂ , elemental bromine (Br2) and/or iron chloride compounds. Some manufacturers do additional processing to reduce the chlorine to chloride and to remove the iron.

 

[chem geek]

This paper posits that the yellowish color is from molecular chlorine, Cl₂, and from iron chloride complexes such as FeCl₂^-. The variation between brands is mostly likely due to varying amounts of iron. Because of the very high chloride content and acidic conditions it probably doesn't take a lot of iron to show up with some color so in terms of how much is getting into the pool it's probably not very much. But yes, the yellowish color means they've got contaminants, probably iron. A high quality HCl will be clear.

 

[Wildcat]

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I have a lingering question that I have not found a satisfactory answer to. I have noticed that, depending on where I get my MA from, it can be varying shades of yellow. If I buy the stuff from Leslie's Pool Store, it is often a very bright yellow. The first time I got it, I thought they put a colorant into it for safety purposes. If I buy the refillable HASA stuff from e-Konomy Pools (local Tucson shop), it is a very pale/straw-yellow. If I splurge and waste...um I mean, spend money at Patio Pools, the MA is crystal clear (same is true about MA from Ace Hardware). From my research lab days, we bought reagent-grade HCl and it was also totally clear. All of it is marked as 20 Baume, 31.45% HCl.

I also know that the manufacturing process for making HCl does contain (or should contain) a step for iron removal as Fe-salts are a known contaminant from the manufacturing process. So, does the yellow color of the HCl indicate a poorer quality material with possible iron contamination?

Got HASA brand from Leslie's in Oro Valley. Made in Eloy, AZ. Totally clear. All the others I have bought there were shades of yellow. First time they sold this brand as far as I remember. 31.45%

BTW, 577 posts since May 2105! You have been busy.What did you do with your time before joining?

 

[JoyfulNoise]

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Got HASA brand from Leslie's in Oro Valley. Made in Eloy, AZ. Totally clear. All the others I have bought there were shades of yellow. First time they sold this brand as far as I remember. 31.45%

BTW, 577 posts since May 2105! You have been busy.What did you do with your time before joining?

Yeah, the Patio Pools stuff is HASA (just not in refillable bottles which is why I like e-Konomy). I'm guessing Leslie's is trying HASA out because previously all their MA was Leslie's branded stuff. I complained about the color once but the sales guy just blew it off and gave me the bogus response that the yellow color is proof that it's the correct concentration. He said the clear stuff can't be trusted. I just let him babble on knowing that what he was saying was total cow pucky. They really do assume their customers are idiots based on how many lies I have been hit with over the years.

As for the number of posts, well, I'm blessed enough to be a stay-at-home dad with three very energetic little boys. The pool is an absolute necessity in cutting down that energy which seems to grow exponentially with their age. I'm also a former engineer with a chemistry/engineering and software background so being on a pool forum and being able to contribute to the conversations is lots of fun. That being said, TFP teaches me more interesting information everyday than I could possibly contribute so I think it's better than the continuing education courses offered at the local community college


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[JoyfulNoise]

The color can come from chlorine Cl₂ , elemental bromine (Br2) and/or iron chloride compounds. Some manufacturers do additional processing to reduce the chlorine to chloride and to remove the iron.

This paper posits that the yellowish color is from molecular chlorine, Cl₂, and from iron chloride complexes such as FeCl₂^-. The variation between brands is mostly likely due to varying amounts of iron. Because of the very high chloride content and acidic conditions it probably doesn't take a lot of iron to show up with some color so in terms of how much is getting into the pool it's probably not very much. But yes, the yellowish color means they've got contaminants, probably iron. A high quality HCl will be clear.

Thank you both!! Too bad there isn't a way to differentiate the free chlorine from the iron. I'm okay with smelling and adding chlorine, iron I'm not so happy about. But as you say, it's probably a vanishingly small amount.


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[JoyfulNoise]

This paper posits that the yellowish color is from molecular chlorine, Cl₂, and from iron chloride complexes such as FeCl₂^-. The variation between brands is mostly likely due to varying amounts of iron. Because of the very high chloride content and acidic conditions it probably doesn't take a lot of iron to show up with some color so in terms of how much is getting into the pool it's probably not very much. But yes, the yellowish color means they've got contaminants, probably iron. A high quality HCl will be clear.

That paper worries me because it claims that the iron contaminant in that German facility is 6ppm. That seems awfully high. I hope the MA we buy around here is substantially lower as I use a good deal of acid annually.

I have contacted HASA by email (did not realize they have a local facility here in AZ) and asked if they publish product purity data. If they respond with any pertinent information regarding free chlorine or iron levels, I'll report back to this thread.


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[Wildcat]

Yeah, the Patio Pools stuff is HASA (just not in refillable bottles which is why I like e-Konomy). I'm guessing Leslie's is trying HASA out because previously all their MA was Leslie's branded stuff. I complained about the color once but the sales guy just blew it off and gave me the bogus response that the yellow color is proof that it's the correct concentration. He said the clear stuff can't be trusted. I just let him babble on knowing that what he was saying was total cow pucky. They really do assume their customers are idiots based on how many lies I have been hit with over the years.


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I spaced out, the HASA purchase was at Patio Pools, not Leslie's. I normally don't go to Patio as they are expensive, but the MA was a good price, like $10 for 2 gal. Whereas bleach was way expensive

 

[JoyfulNoise]

Yeah, I like going to e-Konomy because you get the four 1 gallon refillable containers for $19 (with an initial, one time $6 deposit for the safety carrier that is refundable). So it $4.75 per gallon which is a nice cheap price. However, the refillable stuff is a very pale yellow while the disposable ones in the cardboard boxes (two 1-gallon milk jugs) you get at Patio is typically clear.

Perhaps the bulk delivery and on-site storage of the MA at eKonomy has something to do with it OR HASA has different grades for retail sale versus bulk. I'll keep digging to see what I find.


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[jblizzle]

Just bought some from Leslie's on ina today. Unlike a few weeks ago, this was "desert formula", clear and 29%. Usually it was yellow and the 31% stuff. $11.50 ... Sounds like patio might be cheaper. Better than paying $10 for the 14% stuff at Lowe's.

Wish e konomy was not so far away.

 

[chem geek]

That paper worries me because it claims that the iron contaminant in that German facility is 6ppm. That seems awfully high.

6 ppm iron in a gallon of acid is absolutely nothing to worry about since it will be diluted in thousands of gallons of pool water. To get to even 0.06 ppm iron in a 10,000 gallon pool you'd have to add 100 gallons of this acid.

 

[chiefwej]

This answered a question I had. Leslie's here on Cortaro now has what is labeled as "White" muriatic acid.

 

[JoyfulNoise]

6 ppm iron in a gallon of acid is absolutely nothing to worry about since it will be diluted in thousands of gallons of pool water. To get to even 0.06 ppm iron in a 10,000 gallon pool you'd have to add 100 gallons of this acid.

As always you are quite correct. The math says there's nothing to worry about. I'm just being a bit OCD about the MA product and I'm curious if HASA will share any information about their trace impurity analyses.

This answered a question I had. Leslie's here on Cortaro now has what is labeled as "White" muriatic acid.

Aside from my OCD about the color and wanting no iron at all (not very reasonable I suppose), I do find your post and Jason's posts interesting regarding the labeling of what appears to be low-Fe Muriatic acid as "White" or "Desert Formulation". Makes me wonder if LSP was getting push back from some customers on their yellow MA (more informed pool owners perhaps?) and decided to try other manufacturers or different product grades?

I would expect lower Fe MA to cost a little extra as seen in the local price difference between bulk refillable versus disposable ($4.75/gal versus $5.50/gallon) as that would likely account for the lower manufacturing yields and increased unit costs caused by additional processing steps at the manufacturer (not to mention the additional cost for disposable milk jugs). However, let's hope it doesn't get as bad as some hardware stores that try to market half-strength MA (15%) as "green" or "low fuming" for the same price as full strength That is truly a rip-off.



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[chem geek]

It's really not that difficult to make Muriatic Acid with little or no iron since it's very similar to making chlorinating liquid or bleach with no metals and anyone in the chlor-alkali business is well aware of that because metal ions degrade chlorine much more rapidly and produce oxygen gas which bloats/vents the containers (so more chlorine is vented as well). Just as chlorine gas is added to a solution of lye so that solution needs to start with water free of metals, Muriatic Acid is made from HCl gas added to water. So in both cases one needs to use water free of metals.

 

[JoyfulNoise]

It's really not that difficult to make Muriatic Acid with little or no iron since it's very similar to making chlorinating liquid or bleach with no metals and anyone in the chlor-alkali business is well aware of that because metal ions degrade chlorine much more rapidly and produce oxygen gas which bloats/vents the containers (so more chlorine is vented as well). Just as chlorine gas is added to a solution of lye so that solution needs to start with water free of metals, Muriatic Acid is made from HCl gas added to water. So in both cases one needs to use water free of metals.

Agreed. If I've read about the HCl manufacturing process correctly, I believe the metal contamination comes from the process equipment itself. Gaseous HCl, like a lot of hazardous gases I worked with, will almost certainly be delivered and transported using the appropriate grade of stainless steel tubing. I forget the OSHA standards but any hazardous gas delivered at even modest pressure (15psi or greater) must use SS tubing with appropriate chemical fittings (VCR type fittings). As well, I'm sure there's plenty of other sources of Fe exposure.

So perhaps the degree of iron contamination in the HCl is more indicative of poor manufacturing processes as opposed to precursor materials.

I really do hope HASA responds to my inquiry.


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[gilbee]

I really do hope HASA responds to my inquiry.

Did you ever hear back? My most recent purchase of yellowed MA reminded me of this thread....

 

[BuckeyeChris]

Just bought some from Leslie's on ina today. Unlike a few weeks ago, this was "desert formula", clear and 29%. Usually it was yellow and the 31% stuff. $11.50

Yep, same here.

 

[JoyfulNoise]

Not a word from Hasa. I'm disappointed, I at least expected to be put on their spam list....I guess I'm not even spam-worthy


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[jblizzle]

It sure seems like the clear 29% I got last time is not dropping the pH nearly as much as the yellow 31% the store used to have.

 

[JoyfulNoise]

It sure seems like the clear 29% I got last time is not dropping the pH nearly as much as the yellow 31% the store used to have.

I'll second that notion. I used to get clear stuff that was labelled 31.45% from Patio Pools and it always seemed to take a little more than what PoolMath predicted. Then I started using this yellow stuff from eKonomy and, it not only fumes and smells stronger, but it seems to hit the pH target exactly as PoolMath predicts.

I can't imagine why it would do that and ice only got a subjective vibe to go on but I swear the clear stuff is weaker.


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