# 29% acid vs 14% acid

#### ddas

##### Well-known member
My local Lowes and Home Depot both carry muriatic acid (Kemtek) which is 14.5% HCl, and it's about \$10 for two 1-gallon containers:

http://imgur.com/WLzHEIO

...and now I just discovered a smaller local hardware store (Do-It Center) carries a different Kemtek box which is 29% HCI and it's also about \$10 for two 1-gallon containers!

http://imgur.com/RluHPuf

But before I jump on this, I'm wondering about something. The first one says it contains 8.94 lbs of HCl per gallon. The second one (strangely) says it contains 9.56 lbs of HCl per gallon.

Any chemists care to explain this to me? Is the second box double the strength of the first box (while being the same price)? Or is it only marginally more effective?

Just wondering as I'm always looking for ways to save money. I know I could test this myself by measuring pH before/after using either version, but that'll take several days and I'm just wondering if anyone's got the answer off the top of their head.

#### easttn

##### Well-known member
I dont qualify or claim to be a chemist but I can answer your question.

HCl (lower case L not an upper case I) is hydrogen chloride or hydrochloric acid. It is a gas dissolved in water that is called muriatic acid that lowers the pH. The more gas thats dissolved the stronger it will be.
That is why 8.94 lbs of HCl per gallon is 14.5% and 9.56 lbs of HCl per gallon is 29% and yes 29% is double strength and your best deal.

Have a look at pool math and it will show you 1/2 the dosage when you switch between the two:
http://www.troublefreepool.com/calc.html

And also you can figure which is the better deal:
http://jfhtm350.webs.com/pool/ChemicalCostCalculator.html
And it appears the 29% is the better deal between yours and the 31.45% MHawk suggested.

#### zethacat

That was a typo -- its actually \$10.98 for a 2 pack at Home Depot, and that's what I buy. Just don't store it indoors, in your garage, near chlorine or anywhere near anything that could potentially rust like pool equipment.

#### jmastron

My Home Depot has both 31% (labeled "Contractor Strength") and 14.5% (labeled "Pool") in 2-gallon boxes, often mixed together in the same stack, so have to pay attention to which I'm buying. The 31% contractor strength box is around \$12, and the 14.5% pool box around \$11, so it's clearly a better value to get the contractor strength -- but after accidentally buying the lower strength stuff, I found it a lot more pleasant to work with, much less fumes. So it's a tradeoff whether the premium for the lower strength is worth it, given the amount used isn't as high as bleach.

#### zethacat

jmastron, not sure what you're buying, but you're overpaying by a buck. the link above is correct, here it is again http://www.homedepot.com/p/Smart-2x1-Gallon-Muriatic-Acid-2118-HD/100119310 It costs the same no matter which home depot you buy it from, and it's outside with the pool stuff. It's the same as the "contractor strength", which is 31.45% 20 baum. Unless you're saying \$12 after taxes, in which case that sounds about right.

#### easttn

##### Well-known member
Sounds like Im overpaying. the 31.45 and 14.5 are both \$7.29 for 1 gallon here at Lowes. No 2 gallon pack and no Home Depot close by which they are usually across the street from Lowes but not in this town.

#### Patrick_B

TFP Expert
Sounds like Im overpaying. the 31.45 and 14.5 are both \$7.29 for 1 gallon here at Lowes. No 2 gallon pack and no Home Depot close by which they are usually across the street from Lowes but not in this town.
Indeed!

31% runs about 8.00/Gallon here, but I buy mine from a local PB Supplier for 5.20...thanks to my PB who got me turned on to this. Next season, I plan on trying it in bulk-55 Drum and splitting it with my Pal. It's unbelievably cheaper that way.

#### MARCO...polo

Timely thread as I have been curious as to whether or not the big box stores in NorCal were only allowed to stock 14.5 as that is all I have seen locally. This doesn't include the products in the Paint Dept. From jmastron's post above I was surprised that Sacramento HD (60 miles to the NE) does stock 31.45. I recently got some 31.45 at one of the local Leslie's for \$13.50/box (\$6.75/gal)

#### jmastron

jmastron, not sure what you're buying, but you're overpaying by a buck. the link above is correct, here it is again http://www.homedepot.com/p/Smart-2x1-Gallon-Muriatic-Acid-2118-HD/100119310 It costs the same no matter which home depot you buy it from, and it's outside with the pool stuff. It's the same as the "contractor strength", which is 31.45% 20 baum. Unless you're saying \$12 after taxes, in which case that sounds about right.
Actually, the price does appear to vary -- if I "make my store" a Dallas store, the link above shows \$10.98 for the 2x1-gallon (and the 14.5% pool stuff doesn't come up in a search), but if I set it back to my Sacramento store, the same link shows \$11.98, with the 14.5% Kem-Tek box at \$10.98. So I stand by my rounded prices, and am jealous of your better price

Also, at least when I last bought acid (a month or so ago) the 31% I bought was Kem-Tek brand in a box (at the same \$11.98 price as the Sacramento-link above), with "Contractor Strength" or "Pool" and the ingredient list being the only difference. I don't know if they had the "Smart" bottles elsewhere or if stores just stock equivalent commodity items without that feeding back to the web inventory. I'll take a picture of the mixed pile next time I'm there

#### jblizzle

TFP Expert
This is the one thing I still buy at the pool store as it is 31% for the same price as the weak stuff from the box stores.

#### jmastron

Kem Tek Contractor Strength Muriatic Acid is 29%
http://www.homedepot.com/catalog/pdfImages/6b/6b360557-7bfb-4b68-ac46-748a5cc9a68f.pdf

Kem Tek Muriatic Acid is 14.5%
You're probably right; I was glossing over the difference between 29% and 31.45% as all "high strength", but it is 8%, potentially significant depending on price. Now I'm curious to see what's in my HD, will have to go check soon.

And while I was annoyed when I realized I'd paid almost as much for the "low strength" 14.5% stuff, my other point remains that it was also more pleasant to use, so I might decide the few dollars a month difference is worth it. It goes against my careful spreadsheeting of all local chlorine prices and concentrations to save \$2 a week though!

##### Well-known member
Sorry to drag up an old thread, but this is what came up when I searched..

So I was going to ask if anyone knew of a Better/Bulk price to get Muratic Acid. But I think I might have already paid the best price...

I get 31% Muratic Acid at Menards for \$3.99/Gal. Lowes and HD have 31.45% for \$7.99/Gal.

I was hoping to maybe find a bulk 3-5g, but have yet to find it available in bulk or cheaper than \$3.99/Gal..

#### Richard320

TFP Expert
Sorry to drag up an old thread, but this is what came up when I searched..

So I was going to ask if anyone knew of a Better/Bulk price to get Muratic Acid. But I think I might have already paid the best price...

I get 31% Muratic Acid at Menards for \$3.99/Gal. Lowes and HD have 31.45% for \$7.99/Gal.

I was hoping to maybe find a bulk 3-5g, but have yet to find it available in bulk or cheaper than \$3.99/Gal..

Wrestling a 25-40 lb jug of acid sounds risky to me. Transferring it to a smaller container to pour just doubles the exposure and means you need an acid-proof spigot or pump. I'd stick with gallons.

#### ddas

##### Well-known member
\$3.99 is a great price for either concentration of muriatic acid. In my state (CA) they don't sell that high a concentration nor does it ever go down to that price.

I'm the OP here, who was asking about 29% vs. 14%. Lately I've been buying 14% because the 29%, although more economical, is SO much more concentrated and I smell it a lot as I pour it, and I see the residue of the acid fizzle as it hits the pool, and I'm just thinking...this can't possibly be that healthy for me to breathe a bit of it and also have some of its vapors hitting my clothes.

I'm not a chemist so maybe it's not that huge a deal, but I don't use a huge amount of acid so the difference in cost/efficiency isn't all that much to me. If it saves me \$50 over the course of a year to use the higher concentration, I don't know that it's worth it.

#### abovegroundfan

##### New member
31.45% muriatic acid is the best for the price plus it saves space more chemical.

TFP Expert