22 April 2009

Acid is Dangerous!Those of you with hard water have no doubt encountered one of the most annoying problems ever: descaling appliances.

Sure, calcified bathtub superscum is also seriously annoying, but there are plenty of products out there that will magically descale and de-scum your bathtub with a few sprays and some waiting. It’s the appliances that are particularly annoying to clean – appliances like coffee makers and water distillers.

There are a number of different products available for removing rock-hard mineral deposits from your gizmos, but how do you know which one to use to make your life as easy as possible? You don’t! Otherwise, what the heck are you reading this for? But now you will know soon enough…

First of all, I should note that most of the acids I’m going to mention here are dangerous, and they will burn and horribly maim you if you aren’t careful. So, for the love of frickin’ Jesus, wear thick rubber gloves and safety glasses. Yes, you’ll look like a bonehead in your safety glasses, but that’s better than being blind. How do I know? Have I been blind before? No. But I have a blind friend, and he told me so.

The type of acid you should use depends on the appliance, the severity of the mineral deposits, and the materials from which the appliance is constructed.

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For example, people generally clean coffee makers by brewing a nice fresh pot of vinegar. Vinegar contains acetic acid, which is a fairly weak organic acid. Nevertheless, sometimes acetic acid is enough.

In other cases, you may want to purchase a commercial iron/coffee maker descaling product. Normally, this type of product comes in liquid or crystalline form. The key ingredient is usually sulfamic acid, an organic acid that is used for all kinds of interesting things. Sulfamic acid is an excellent descaling agent, and it is much safer for various types of metals. When strong enough, it will even remove rust (try it!).

Sulfamic acid is, in fact, my acid of choice for most applications. When it comes to sulfamic acid, the crystalline white powder kind that comes in a packet is the best. The simple reason for this is that what you are getting is basically sulfamic acid and nothing else. You dissolve the crystals in water, and voila! You have a glorious descaling solution. There are also liquid descalers that contain sulfamic acid, but alas, they also contain other cleaning agents and stabilizers in order to keep the sulfamic acid in a liquidy state. Go for the crystalline stuff!

Now, sometimes, you have an appliance like a water distiller. Water distillers are fabulous contraptions for generating super-pure drinking water. Contrary to popular belief, drinking distilled water is NOT bad for you. I should know: I’ve been drinking nothing but distilled water for two years now, and I feel great! I am in perfect health. The reasons for why distilled water is actually good for you are beyond the scope of this post, but you can find a bunch of info on the subject by doing a simple web search.

In any case, water distillers for the home usually work by heating water with an electric element inside a sealed metal container. The water boils, the steam rises into a spiraling tube, a fan cools the tube, the pure water condenses, and it trickles down into the water reservoir. As you can imagine, what is left in the boiling chamber is a whole lot of nasty, crusty, rock-hard mineral deposits jam-packed with whatever other evil crapola is in your tap water. Cleaning those deposits is not easy, since it is literally rock hard.

This is where sulfamic acid comes in. It has to be VERY highly concentrated. In other words, dump in lots of packets of the white crystals! It works great, and it’s far more friendly for the metal boiling chamber and associated components.

However, sometimes, the mineral deposits are just too hard, or you don’t have hours to wait for the descaling process. In that case, go out and get yourself some hydrochloric acid, commonly known as muriatic acid. It’s the same stuff your belly uses to help digest food.

Hydrochloric acid is seriously evil stuff (except when it’s in your belly). You’ll see this for yourself when you catch a whiff of the noxious odors coming out of your calcified appliance when you pour in the diluted acid. Hydrochloric acid will eagerly eat through things like certain rubber seals, so be careful. It also has a bad habit of eating away at certain metals, so it must be used with caution. You don’t want to just willy nilly dump it full strength into some flimsy plastic reservoir and watch as your plastic container slowly dissolves. On the plus side, this is one acid that does not mess around with even the hardest mineral deposits.

Whatever acid you use, you will probably have to drain the acid, flush with water, and possibly use a metal utensil to poke and prod at any remaining deposits. They should just fall right off your appliance at that point. Flush with more water, and then place the gizmo back in service.

Of course, you can also use a container with acid in it to clean off calcified components, pipes or fittings, etc.

Stick with sulfamic acid if you can, since it’s the most friendly – in more ways than one. But whatever acid you use, be careful!!!

Descaling Appliances: Which Acid is Best?
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31 thoughts on “Descaling Appliances: Which Acid is Best?

  • 6 December 2013 at 13:30
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    Dear Descaler expert,

    I am quite impressed with your findings it is really very informative and you have given a birds eye view of acids use in very few lines it will definitely help the mankind.Keep it up keep sharing.

    Best Regards
    Ghulam Abbas Cyclewala(Chemical Engineer)

    Reply
  • 9 April 2014 at 15:19
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    I love this info. However, for industrial application purposes, can you come out with dosage rate in terms of % or ppm or required pH for effective cleaning.

    Reply
  • 30 April 2014 at 05:36
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    I use muriatic acid to descale my commercial espresso machines. I buy it at home depot. I think it is 20% strength, but not 100 percent sure of that. I further dilute this to about 4 parts water to 1 part acid. In a plastic 5-6 gallon bucket I place the water first ****always water first***** then the muriatic acid. In a separate 5-6 gallon bucket, I just fill with water and dump in a large box of baking soda and mix it up. After about 5-7 minutes of soaking the parts with scale in the acid, I dip them into the baking soda (base) bucket. The baking soda neutralizes the acid and does an awesome job of removing the scale. Then I rinse with lots of water. I use wire coat hangers to attach to the parts to keep my hands away.Safety goggles are a must!!! When you dip the parts in to the base bucket, a chemical reaction occurs, and you get some violent splashing of the neutralizer and acid. I will say, it is fun! Yep…fun! Some boilers have a nickel coating on the copper, just be careful not to soak these parts for more than a few minutes, or the nickel coating will dissolve. Copper will melt away if left to long. If all of the scale doesn’t come off the first time, you can always resoak the parts. Just use short intervals to prevent damage.Common sense is key! At the end of my descaling, I pour the baking soda water into the acid bucket and this neutralizes what is in the bucket. This is the real fun! Just don’t wear nice shoes when you do this…Good Luck! Hope this helps.

    Reply
  • 20 June 2014 at 18:57
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    Hi

    Which will be a strongher acid between sodium gluconate Sulphamic Acid

    Currently I am using Hydrochloric acid & Sodium Gluconate. To clean oil coolers & Radiators

    Thanks

    Selva

    Reply
  • 7 July 2014 at 18:08
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    Dear Selva,

    I have at times advised Phosphoric Acid , it does work faster and is safer than Hydrochloric Acid.

    Best Regards
    G.A.Cyclewala

    Reply
    • 15 February 2019 at 22:11
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      It also will etch glass, I do not think it is “safer” than hydrochloric. Both will eat your skin, eyes, hair etc in a heart beat if you do not use proper precautions. Also ALWAYS ADD ACID TO WATER NEVER THE REVERSE.

      Reply
  • 15 August 2014 at 01:15
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    Hi GA

    Thanks for your advise!

    Can I mix Phosphoric acid & sodium sodium gluconate together

    Reply
  • 22 December 2014 at 08:17
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    what is optimum conceteration of sulfamic acid for using in RO unit as antiscaling agent

    Reply
    • 22 December 2014 at 12:04
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      I have no idea, but I solved the hard water problem by putting a water softener in front of the RO unit. Now the RO lasts forever. 😉

      Reply
  • 14 April 2015 at 18:46
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    Hello Scotte, I wanna use Phosphonic(not phosphoric) Acid for Aluminium washing. Do you have any idea which kind of Phosphonic acid is better for this purpose?
    Thank you

    Reply
  • 8 June 2015 at 20:14
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    I’m on a quest to effectively clean, rather than replace, my humidifier filter belt! And I don’t like spending more money for products that are less effective than the basic ingredients they contain. Obviously one has to be careful using the strong stuff, but whatever works best, I want to know what it is. Your article has helped tremendously, thanks!

    Reply
  • 26 July 2015 at 20:32
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    I also use Muriatic Acid to clean with, because of the hard water here in Tampa.
    I dilute it one part acid to 4 parts water, and use it just like vinegar, followed by a couple of really good rinse brews.
    Use safety glasses, because you will hit the roof if it gets in your eyes during the cleaning cycle.

    Reply
  • 10 March 2016 at 00:07
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    I’ve got a hot tub that has a combination of heavy calcium scale & chlorine stains. Is there a safe & easy way to remove these stains without causing damage to the tub?

    Reply
  • 16 March 2016 at 23:00
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    CLR and other Sulfamic Acid containing cleaners are the best at removing heavy scale and stains. You’re not seeing chlorine stains but rather iron stains that are yellow and orange. Those cleaners can be quite irritating so make sure you have the bathroom fan running while you are using it. Spray the cleaner or apply it to a wet sponge and apply it so the entire surface is covered. Sulfamic Acid will not damage fiberglass or lined tubs but be careful as it will etch marble and probably other tile surfaces. Allow the chemical to work on the stain for 30 minutes or so and scrub after application. Rinse thoroughly before use.

    The key ingredient is Sulfamic Acid. For heavy hard water stains, foam cleansers, vinegar, Barkeeper’s Friend, and other relatively mild cleansers just aren’t effective.

    Reply
  • 16 March 2016 at 23:06
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    Phosphoric Acid is Phosphoric Acid. You may be referring to the strength or concentration of the acid. I would think you could effectively clean aluminum with 5-10% /v Phosphoric Acid. Also try Naval Jelly which is available retail.

    @Miti

    Reply
  • 26 July 2016 at 01:40
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    It’s not distilled water that is dangerous… It’s deionized water or water of higher, organic chemistry lab purity (MilliQ). These waters strip minerals from your system when consumed.

    Distilled water is just evaporated and recondensed. It still contains some minerals, included compounds it leaches from metal and plastic containers.

    Reply
  • 17 August 2016 at 14:36
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    Hi there! I have a laboratory water still that has a nickel element. I am currently cleaning it with HCl as the scale is 1 – 2mm thick. I would like to change to a weaker acid to prolong the nickel coating. Would you recommend sulphamic acid? (The scale is pretty thick)

    Reply
    • 17 August 2016 at 14:48
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      Sulphamic acid is used in a lot of household cleaners at low concentrations, and it does appear to be safer (and weaker) than HCl. Well, I’m no chemist, but I’d give it a whirl!

      Reply
  • 17 August 2016 at 14:54
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    Thanks Scottie! Will let you know.

    Reply
  • 8 December 2016 at 16:13
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    @Adrian
    Nickel safe ice machine cleaners are a combination of <50% Phosphoric acid mixed with either <10% Sulphamic or <5% Glycolic acid. Available for around $30 – 35 / gal. 16 oz mixed w/3 gal water safely cleans our ice machine and doesn't harm the nickel. The brand I usually use Ace has Glycolic but it' isn't available locally this time and the brand I found has sulphamic. I stumbled on this very good post while trying to decide whether or not to buy the new brand b/c I wasn't familiar w/suphamic acid. I thought this info might be helpful to some who might want to use the pre-mixed for other purposes.

    Reply
  • 19 September 2017 at 09:13
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    Citric acid powder mixed with hot water is an excellent kettle & washing machine descaler.
    Add 1 teaspoon to kettles once per week (then boil) to keep kettles clean.
    Add 50g to washing machines on a 90-95C cotton hot cycle, every 6-8 weeks to keep washing machine filaments descaled / drums clean.
    Citric acid is less aggressive, less harmful to the environment, doesn’t affect appliance seals.
    Use regularly for best results.
    Dishwasher cleaners contain Phosphoric Acid, Anti Corrosion Inhibitors, Ionic Surfactants, Non-ionic surfactants, Fragrance, Water.
    Sulphamic acid is excellent for cleaning metal systems where a more aggressive acid is required.
    It is also excellent at cleaning ceramics i.e toilets.

    Reply
  • 23 December 2018 at 20:38
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    Do you have any recommendations for hard water, like seriously hard water, on tile or fiberglass and metal? We’re a housecleaning company here in CA and are having a hard time finding a product that the cleaners can take with them to all their cleaning jobs. I don’t want something that’s so dangerous but we need something strong enough that they’re not wasting all their time SCRUBBING for hours. We live in the mountains so most of the houses live on wells…. lots of hard water build up. Thanks so much! -Triya

    Reply
    • 23 December 2018 at 20:58
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      That’s tricky. Acids can discolor or damage different materials, and they still can take a long time / large quantity to fully dissolve lots of build-up.

      I would just use something like CLR. Unfortunately, scrubbing is still required in my experience, but at least it doesn’t eat through anything.

      Reply
    • 1 March 2019 at 21:56
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      I also clean houses professionally, but even before I started cleaning houses professionally, hands down my tried & trusted #1 “go to” has always been steam! There is very little that will withstand the power of hot steam coupled with mechanical action.

      It may not be the cheapest option in terms of the cost of good steam cleaners, but it’s the safest & most effective option for most household cleaning tasks.

      Make sure the units are of decent wattage (1200w is acceptable –certainly better than the 1000w units– but 1500w , or more, if they exist, is ideal). It should also have various brush attachments of varying hardnesses (with nylon bristles for delicate surfaces, brass or stainless steel for hardcore cleaning such as BBQ frills, concrete, etc.)

      And a decent sized water reservoir for the purposes of professional cleaning will be more efficient as there will be less downtime while refilling and waiting for it to reheat… though other tasks can always be done in the meantime anyways.

      For most tasks you’ll find steam, coupled with the mechanical action of scrubbing with the brush attachments will not only be sufficient, but if you’ve never cleaned with a steam cleaner then you’ll be pleasantly surprised by how easily it will remove years of built up grime.

      There’s nothing safer than that (unless you don’t use common sense and understand what scalding water can do to human skin)… but even so, there will be the more demanding tasks that will require the use of chemical cleaners (natural or man-made).

      In those instances, steam will STILL be your best friend. After you’ve hit the mess with steam action you’ll then see what’s left in need of something stronger and choose your cleaning product/acid accordingly.

      And the steam will have significantly softened or loosened the offending mess so then the cleaning product/acid can step in afterwards to give it a double whammy in a faster and more effective manner.

      That said, lately I’ve also been a fan of using oscillating action as the means of mechanical action. I don’t mean those gimmicky spin brushes (to be fair, I’m sure they serve their purpose for basic cleaning) but oscillating beats it out NY FAR as it’s the vibrational action that loosens dirt & debris like nobody’s business. When combining forces with acids, again use common sense.

      A milder acid like paracetic, citric, or oxalic aren’t too worrying to have splashing around a bit while using an oscillating cleaning tool –of course you’ll still want to use gloves & goggles to be safe, and mind the types of surface(s) you’ll be cleaning or that are close enough to be negatively affected or corroded, such as marble, granite, chrome, etc.)

      But in the case of stronger acids like muriatic/hydrochloric acid, or the like, it’d be foolish to risk any splashing or sloshing around as the oscillating bristles are kicking up sludgy debris soaked & dissolved in hardcore corrosive acids.

      In those cases, best one after the other with a good rinsing in between. But then again, considering your circumstances and requisites, you wouldn’t be likely to be using those anyways.

      Personally, I’m still waiting for someone to invent a cleaning appliance/tool that combines the benefits of steam action with oscillating vibrational force. That would truly be the “be all, end all!” But alas, it’s yet to become a reality!

      (Though if you’re ambidextrous you can always “double fist” it with steam in one hand and an oscillating tool –think higher-end electric toothbrush specially made for cleaning with brush attachments suitable for the job– in the other hand… while taking care to not direct the steam at any plastic parts for long enough durations that they’ll melt the plastic unless giving the oscillating tool enough intervals of breaks away from the direct path of the steam.

      But even if one is ambidextrous, I’d think it’d still be rather awkward to simultaneously manage both while wielding the weight of the steam cleaning appliance!)

      And while I haven’t truly addressed your question in terms of “safe, effective cleaning products” (as far as liquids, creams, or powders in bottle-form go), I hope this info, while wordy and lengthy (sorry!) is of help to you and others as well!

      Side note: I just realized that I hadn’t even addressed my other favourite miracle accomplice in the plight against nasty messes & stubborn cleaning tasks that are a god-send for both domestic AND professional cleaning purposes: microfiber! But being a professional cleaning company I’m sure you already have that angle well covered!!

      Reply
      • 1 March 2019 at 22:29
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        Well I’ll be a monkey’s uncle… STEAM. I’m gonna try that! Thanks!

        Reply
  • 9 February 2019 at 18:46
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    I am looking for a ratio of sulphamic acid crystals to water % or grammes to descale my marine saltwater propellers and shafts. Props are bronze and shafts stainless steel. Any thoughts?

    Reply
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