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Thread: Muriatic Acid vs Dry Acid

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    Muriatic Acid vs Dry Acid

    I'm just getting started and wondering what the consensus is regarding whether to use Muriatic acid or dry acid. Any thoughts?
    June 2016 remodel IG 14k gal Blue Surf Pebble Sheen : Hayward Star Clear Plus C12002 : Pentair Challenger 2HP 1' : Century Pool and Spa Motor 3/4 HP 2' : Pentair Master Temp heater : Polaris 280 pool sweep : TF-100/Speed Stir

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    Re: Muriatic Acid vs Dry Acid

    Muriatic acid is much preferred. The major downside is the fumes, but with precaution should never become an issue.

    Dry acid (sulfuric) adds sulfates to the water which can become very problematic with time. It is also typically more expensive. Sulfuric acid is usually marketed as a safer alternative (no fumes) but possess much greater risk if it comes in contact with the body.
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    Texas Splash's Avatar
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    Re: Muriatic Acid vs Dry Acid

    I'm with Brian. I started with dry acid in my early days when I visited the pool store a lot, but now that I'm on my own with TFP it's MA for me. Much simpler.
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    Re: Muriatic Acid vs Dry Acid

    MA using member #3 checking in for the consensus. Cheaper - Easier
    25 + year pool owner. Current pool (going on 11th year) - 38K gallon in ground Gunite/White Plaster, Spillover Spa, Hayward Cartridge Filter, Hayward 450k BTU NG Heater, Hayward Goldline Aqua Logic control with T-Cell-15 Salt Water Cell, Dolphin Explorer.
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    Re: Muriatic Acid vs Dry Acid

    So do sulfates cause any issues on vinyl pools? It seems like it's all about issues with grout in the threads I've found. The dry acid isn't THAT expensive, so I'd prefer to stay with it if I can.
    20K gallon vinyl inground pool, Hayward Pro Series sand filter, 1 HP pump, Taylor K-2006

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    Re: Muriatic Acid vs Dry Acid

    I don't know of many issues in vinyl pools unless you end up getting scale (which would take high calcium levels and very high sulfate levels) to become problematic. Sulfates are a very bad thing for SWG pools as well. Do you have concrete decking around the pool?

    My knowledge is limited though...
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    Muriatic Acid vs Dry Acid

    Quote Originally Posted by C3Cl3N3O3 View Post
    So do sulfates cause any issues on vinyl pools? It seems like it's all about issues with grout in the threads I've found. The dry acid isn't THAT expensive, so I'd prefer to stay with it if I can.
    Dry acid is sodium bisulfate. After dissociation of the acid salt, it leaves behind the sulfate ion. Sulfates can damage concrete & plaster as well as degrade the coatings on SWG plates. At high enough concentrations, sulfates can react with calcium to form spindly, needle-like crystals of calcium sulfate (gypsum). Sulfates can only be removed by draining water. While its use in vinyl pools is typically not as problematic as in plaster pools, scaling of gypsum crystals can increase the risk of liner puncture.

    You can certainly use dry acid if you wish, but you are adding something to your water that your pool does not need.
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    Re: Muriatic Acid vs Dry Acid

    I use Dry Acid, despite the recommendations against with my SWG because I used MA once and was overwhelmed with fumes. I live in a very windy area of the country, the air is seldom still, and the wind only stays in one direction if there is a storm. Otherwise it changes direction every couple of seconds. Trying to get downwind of the stuff was almost impossible. My SWG is on it's 9th season with no issues.

    That being said, I use acid seldom, maybe once or twice a year. But I have a problem with pH drifting low, not high, I believe because my fill well water is <7. If I had to use it as often as others do, I might get a mask and deal with the MA.
    19,000 gallons, Well Water
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    Re: Muriatic Acid vs Dry Acid

    First person I've ever heard of with a SWG that doesn't get pH rise. Lucky you.
    25 + year pool owner. Current pool (going on 11th year) - 38K gallon in ground Gunite/White Plaster, Spillover Spa, Hayward Cartridge Filter, Hayward 450k BTU NG Heater, Hayward Goldline Aqua Logic control with T-Cell-15 Salt Water Cell, Dolphin Explorer.
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    Re: Muriatic Acid vs Dry Acid

    Quote Originally Posted by mikemass View Post
    First person I've ever heard of with a SWG that doesn't get pH rise. Lucky you.

    My pH stays at 7.4/7.5 all season even with the SWCG. I haven't had to add acid in years since tweaking my TA and adding borates.
    20k IG vinyl liner/Aqua Rite SWCG, T-15 cell/Hayward Pro Grid 6020 DE filter/Polaris 280 with booster pump/Hayward Superpump 1 hp/city water/pool installed March 2004

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    Re: Muriatic Acid vs Dry Acid

    i like to use the Muriatic acid i used dry last year the Muriatic acid made me nervous but since my boy friend is doing that part(this year for me) i use the Muriatic acid now its seems cheaper and seems to work better in my opinion
    13,995 gallons 24 X 52 / above ground pool.../.SWG/ sand filter/ vinyl liner

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    Re: Muriatic Acid vs Dry Acid

    Quote Originally Posted by mikemass View Post
    First person I've ever heard of with a SWG that doesn't get pH rise. Lucky you.
    I rarely have pH rise myself. Perhaps because I run my SWG on very low % compared to others?
    My Amazon Smile for November12K Fiberglass IG, Infinity 4000 automatic cover, SWCG, Hayward Sand Filter, Hayward 1.5 Pump, Doheny Discovery Robot, Savi Melody LED pool lights, outdoor speakers and other assorted doo-dads. Sundance Altamar Hot Tub.
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    Re: Muriatic Acid vs Dry Acid

    Quote Originally Posted by Deb04 View Post
    I use Dry Acid, despite the recommendations against with my SWG because I used MA once and was overwhelmed with fumes. I live in a very windy area of the country, the air is seldom still, and the wind only stays in one direction if there is a storm. Otherwise it changes direction every couple of seconds. Trying to get downwind of the stuff was almost impossible. My SWG is on it's 9th season with no issues.

    That being said, I use acid seldom, maybe once or twice a year. But I have a problem with pH drifting low, not high, I believe because my fill well water is <7. If I had to use it as often as others do, I might get a mask and deal with the MA.
    Be careful with a mask -- there was one person here who put on a full respirator, and ended up with an eye injury that required time and ophthalmologist care to heal; clearly exposed to a lot more fumes than they otherwise would have tolerated.. Honestly I think it's better to not use a mask and to back away as soon as you smell any fumes. I do wear goggles to protect against splashes (but not gloves, because my understanding is that getting it on your skin isn't a major issue if you rinse it off ASAP)

    A good tip is to never pour into a measuring cup; open the jug, float it in the pool, and pour right into the water. I mark my jugs with 1/4, 1/2, and 3/4 lines from a stick I calibrated once with water, then use that to control how much I put in. It doesn't usually have to be exact.

    You can also get lower strength MA -- around here Home Depot sells both 31% and 14% MA in similar 2-gallon boxes; the 31% is $1 more so obviously the better value, but if I had to deal with wind when pouring I'd gladly pay a bit extra for the lower strength; I accidentally bought it once and it does fume a lot less.

    While dealing with liquids has issues, as mentioned dry chemicals can have similar issues (e.g. when you open the bucket of dry acid) or worse.
    21000gal IG plaster, Sacramento CA area (late 1950s/early 60s)
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    Re: Muriatic Acid vs Dry Acid

    Thank you all for your input! Now that I have a lot of money in the pool, the chemistry suddenly matters
    June 2016 remodel IG 14k gal Blue Surf Pebble Sheen : Hayward Star Clear Plus C12002 : Pentair Challenger 2HP 1' : Century Pool and Spa Motor 3/4 HP 2' : Pentair Master Temp heater : Polaris 280 pool sweep : TF-100/Speed Stir

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    Re: Muriatic Acid vs Dry Acid

    +1 to safety glasses for working with muriatic acid, and +1 to muriatic acid for the pool.

    Getting comfortable with MA by using the weaker percentage for a while is a good idea.

    My better half gets a half full pail of pool water first, then adds the acid into that water. This kills the fumes right away. Water from the garden tap would be fine as well. Then she takes the pail to the pool for pouring it in.
    12k IG salt; glass beads in plaster; K-2006C, K-1766, CCL, and Aussie 4in1 (HTH); Pentair Eco800 1.2HP VS; Zodiac SWC 1.3 lb/day (25 g/hr); 25" filter recycled glass; OKU solar panels; 1/2 HP solar pump; Rebel (Warrior) pool cleaner; FlowViz; prior pool AG 10k | Read Before Posting to get the best possible advice | ... and this helped me a lot!: TFPC for Beginners

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    Re: Muriatic Acid vs Dry Acid

    I use muriatic acid and wear sunglasses and hold my breath when I pour than walk away and breathe .
    Inground 22k gallon gunite 15x31 main pool, 15x7 wading pool/sunning deck, hot tub/with overflow (9' octagon with limestone top) & slide NSWG, Aqua Blue Pebble Sheen
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    Re: Muriatic Acid vs Dry Acid

    Quote Originally Posted by needsajet View Post
    +1 to safety glasses for working with muriatic acid, and +1 to muriatic acid for the pool.

    Getting comfortable with MA by using the weaker percentage for a while is a good idea.

    My better half gets a half full pail of pool water first, then adds the acid into that water. This kills the fumes right away. Water from the garden tap would be fine as well. Then she takes the pail to the pool for pouring it in.
    I may be overly paranoid, but I get nervous when I hear people say this, maybe because I'm picturing someone dragging a huge pail of sloshing water+MA (diluted but still very acidic) across the pool deck; seems to invite a lot of changes to spill on clothes, the deck, etc. To me, getting into a stable position at the edge of the pool, opening the MA jug, and pouring it from an inch above the water seems much safer. In the pool, you can put the jug itself partly in the water so the spout is very close to the surface, which you can't really do when pouring into a narrow bucket. I got that technique from people here, after initially doing the pour-into-a-measuring-cup thing until I saw one night by flashlight just how much fume came from doing that.
    21000gal IG plaster, Sacramento CA area (late 1950s/early 60s)
    Filter: Cartridge, Pentair CCP420 (2014)
    Main pump: Pentair IntelliFlo VS (2015)
    Boost pump: 3/4hp (2011), Polaris 280 cleaner (unknown age)

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    Re: Muriatic Acid vs Dry Acid

    Just as a general warning for folks who may want to do it this way- remember to always pour the MA *into* the water, not the water into the MA.
    My Amazon Smile for November12K Fiberglass IG, Infinity 4000 automatic cover, SWCG, Hayward Sand Filter, Hayward 1.5 Pump, Doheny Discovery Robot, Savi Melody LED pool lights, outdoor speakers and other assorted doo-dads. Sundance Altamar Hot Tub.
    Our pool build--> Our Pool Solved Our Sloping Yard Skippy's Cheap Pool Cooler -->Skippy's New Fountain

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    Re: Muriatic Acid vs Dry Acid

    My wife's a bright gal and plenty strong enough to lift a half-full pail! She's a 20-year pool gal with a fondness for clothing I'm yet to entirely comprehend, but I've never even thought about her choice of pail

    No sloshing buckets allowed, unless they're filled with ice and coldies!
    12k IG salt; glass beads in plaster; K-2006C, K-1766, CCL, and Aussie 4in1 (HTH); Pentair Eco800 1.2HP VS; Zodiac SWC 1.3 lb/day (25 g/hr); 25" filter recycled glass; OKU solar panels; 1/2 HP solar pump; Rebel (Warrior) pool cleaner; FlowViz; prior pool AG 10k | Read Before Posting to get the best possible advice | ... and this helped me a lot!: TFPC for Beginners

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