Has anyone ever dealt with limescale in a bathroom sink?

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In summary, you can remove limescale or soap scum from a sink with vinegar, citric acid, or CLR. Pool acid will also work, but be very careful not to get it on bare iron.
  • #1
kyphysics
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If so, how did you know it was limescale and not something else...like white mold, efflorescence, etc.?

I have some weird white residue that is building up on my sink and it is:

a.) hard to remove (you can scrape it, but it takes a lot of work lol)
b.) keeps coming back (granted, I typically haven't taken the time to scrap it all off...so there's some that's left over, b/c my arm gets tired...and maybe whatever it is just keeps growing)

Just seeing if anyone has ever dealt with some weird white chalk-y substance in their sink that builds up...I even have something similar in my shower floor area too!

(p.s. I'd be happy to post a pic too if that'd be helpful for recognition.)
 
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  • #3
Limescale will bubble if treated with an acid strong enough.
 
  • #4
Borek said:
Limescale will bubble if treated with an acid strong enough.
But too strong an acid might actually destroy the material of the sink itself.

Maybe a moderate concentration is best.
 
  • #5
Strong _enough_ was a very careful wording.
 
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  • #6
There are a lot of products meant to clean up accumulations of calcium salts. In the US, try CLR or any product next to it on the grocery store shelf. Read the label. If you are in Europe I'm sure @Borek can recommend something.
 
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  • #7
Those products are acids.
 
  • #8
Ordinary vinegar will attack limescale but not very aggressively.
 
  • #9
Grocery-store and hardware-store products are formulated and available for removing such deposits from bathroom sinks. Also a soft abrasive brush might help. Not know what they are called, but may be made of some foamy-like plastic material.
 
  • #10
kyphysics said:
Just seeing if anyone has ever dealt with some weird white chalk-y substance in their sink that builds up...I even have something similar in my shower floor area too!

I don't know how a mineral scale came to be called "lime" scale, but many white chalky deposits can be removed with lime juice. Cut a lime in half, squeeze a half on a chalky area and set it to rest on that area for half an hour. Then try scrubbing the scale off using the half-lime itself. That will confirm (or refute) the idea that the chalky deposit can be removed with an acid.
 
  • #11
"Lime scale," or soap scum?
 
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  • #12
Bystander said:
"Lime scale," or soap scum?
Lime scale is the hardwater deposits, like found in pipes and sometimes in vessels which are used for frequent or prolonged heating of water.

Soap scum involves soap anions precipitating with the hardness cations, as might occur in showers, toilets (sometimes) and sinks.
 
  • #13
Yea, lived with it as a teenager with well water having 10 to 20 times the 'hardness' of municipal water.

What is called 'lime buildup' or 'mineral buildup' is usually Calcium Carbonate (CaCO3), also known as Limestone and as Chalk. It's found in practically all groundwater and municipal systems in varyiing concentrations. If your water tastes a little like chalk, you have a significant concentration of the stuff.

As mentioned above, the two standbys are Vinegar (Acetic Acid) and Citric Acid (lemon or lime juice). If I recall correctly, the CLR product is Citric Acid.

If using Vinegar, you can sprinkle some table salt (Sodium Chloride) on with the Vinegar. This provides some abrasive action and reacts with the Vinegar to produce some Hydrochloric Acid (HCl), which is more agggresive than the Acetic Acid. (Not particularly dangerous that way. If you have eaten Fish-and-Chips with salt and Vinegar, that's what you taste, the HCl.)

Whatever you use, leave it on to soak for at least several minutes. I've even applied a paper towel to the surface and saturated it with whatever acid I'm using to extend the soak time.

Another possibility is to use denture cleaner but the active ingredient, Phosphoric Acid, may stain some metals. (Phosphoric acid is used to chemically prime Steel for painting (Phosphate treatment), it leaves a gray surface coating. It is also used to remove rust when sold as Naval Jelly.)

If you want vicious activity, get some dry pool acid (used for adjusting acidity of swimming pools). Wet the surface and sprinkle it with a little bit of the acid crystals. Wear rubber gloves, old clothes, and eye protection if using this approach. Rinse area thoroughly afterwards. Don't get it on bare Iron, it will severely rust quite rapidly. Having some Baking Soda around for clean-up and emergencies is a good idea too. It sure is effective though! (Dissolves concrete too.)
 
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  • #14
Another idea is to fix the leaky faucet that's probably causing the buildup ... :smile:
You can get free replacement washers etc. from some faucet mfrs. I have.
 
  • #15
You can easily and cheaply obtain products desinged for this purpose at a local hardware store.
They are usually moderate level HCl with a bit of scent to make it smell nicer,
 
  • #16
Rust removers featuring oxalic acid work very well.
 
  • #17
Investigate sulfamic acid. Don't know what is used in these days, but it was once popular in coffeepot cleaners, for descaling distilled water stills, and is one of the chemicals in CLR.

What you might want to try is apply hypochlorite bleach to one area, and an acid solution to another. If bleach doesn't appear to faze it, but acid does, it is probably limescale.
 
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  • #18
Forget the acids and formulaics, just get a new sink :cry: and install a water softener :kiss:. The former will make your sink shine like new and the latter will prevent limescale from accumulating. If you think getting a new sink is expensive and a bit drastic, consider the cost of the daily treatment with acid and what that does to your health :eek: .
 
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  • #19
Plenty of suggested methods for removing the stuff. I have to second and third the suggestion made by EarthCitizen. If the scale in your sink is magnesium and calcium carbonates, you are using water with high concentrations of the Mg and Ca. These are present in the form of bicarbonates that are formed in your aquifer the same way that formations in caves are formed. Water seeping through the limestone (or dolomite, or marble) contains CO2 in the form of carbonic acid, which dissolves some carbonates because it forms the bicarbonate salt, which is slightly more soluble than the carbonates. Upon exposure to air, the bicarbonate loses one molecule of carbon dioxide. That leaves very insoluble Ca and Mg carbonates, et voila, you are growing cave innards in your sink. Continue with the experiment, or get a water softener. If scale is forming in your sink, then it's also depositing inside all of your plumbing, which become increasing sclerotic, as in arterial sclerosis, just waiting for a bit of gunk to become lodged. Now you have no water at all.
The water softeners I know from my youth contained a cation exchange material. I believe it was a sodium zeolite mineral. Divalent cations like Ca and Mg have a higher affinity for the exchange medium than sodium, so when your divalent-laden water runs through the exchanger, they replace the Na ions in the zeolite. Eventually, the exchanger becomes saturated with divalents and must be regenerated. Regeneration involves making a concentrated brine solution from NaCl pellets you bought at a hardware supplier and circulating it through the calcium form of the exchange medium. The exchanger is then rinsed with water and the solution of Ca, Mg chlorides are the washed down the drain. Since I was a chemistry enthusiast in my youth, the process wasn't as laborious as it sounds for me. It was one chore I didn't mind doing, and that was only every month or so. BTW, the scale probably does have some Ca,Mg soap in it. This particular gunk is another reason people use water softeners. The divalent soap scum forms on your body and hair when you wash, and is rather unpleasant and not the best kind of soap either.
 
  • #20
Commercial products work fine...the trick is to leave them in place and give them time to desolve the limescale. Don't expecte to just spray and wipe a few seconds later, real life is not like the TV adverts where it works instantly. Spray and leave in place for 10/15 minutes.
 
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  • #21
MikeeMiracle said:
Commercial products work fine...the trick is to leave them in place and give them time to desolve the limescale. Don't expecte to just spray and wipe a few seconds later, real life is not like the TV adverts where it works instantly. Spray and leave in place for 10/15 minutes.
Don't think the OP expected the products to "work like on TV"! She states "hard to remove (you can scrape it, but it takes a lot of work lol)". As Mark and I stated above it is best to avoid these commercial products... they are not good for your health, especially if you are asthmatic or have allergies/sensitive skin. Additionally, they will affect and corrode metal/chrome bits in the bathroom (eg tap, waste pipe etc).
 
  • #22
MikeeMiracle said:
Commercial products work fine...the trick is to leave them in place and give them time to desolve the limescale. Don't expecte to just spray and wipe a few seconds later, real life is not like the TV adverts where it works instantly. Spray and leave in place for 10/15 minutes.
This is why some of the products come as a thickened (viscous) liquid, sticky, so that once sprayed, will stay in place, more or less, for a minute or two at least.
 
  • #23
The process described by @Mark Harder is now done automagically in modern water conditioners. Once a month or so you dump a 20kg or 40kg sack of conditioner salt into a holding tank, and software does the rest. When brine is needed, water fills the holding tank long enough to saturate with NaCl, then the rest runs by itself. Once there's no more solid to dissolve, another sack is needed. I suppose recent models will email you when it's time to deal with that.
 
  • #24
Apologies for the belated response everyone. Was very busy with a new summer job and had sort of forgotten about this thread I posted.

Borek said:
Limescale will bubble if treated with an acid strong enough.
Borek,
I've only tried using bleach and and distilled white vinegar on this "white stuff" that is in my sink and shower. I poured it on the white stuff (which means it only stayed on it for a few seconds, before going down the drain). I did pour a lot though and multiple times from small cups. I can't find a sink drain/pipe plug that fits my sink to allow me to fill it up and "soak" the white stuff for a long time, before trying to remove it. I think Home Depot has a stopper that fits, though. Going tonight to try to buy one.

Bleach seems to dry it out. The vinegar seems to "dissolve" some of the white stuff (like surface level only), but most of it remains.

With vinegar, something VERY weird happened, however. After pouring it on the white stuff and seemingly seeing some of it dissolve, I also immediately (upon pouring) noticed some tiny black dots that magically "emerged" on it. It made me wonder if the dots were underneath the white stuff and after dissolving the "top layer" they were revealed. Or, could it be the vinegar interacting with the white stuff produced these weird black dots?

In either case, I still get this white "growth" every 3-4 days. It "grows" very fast. I threw away a few sink strainers too, because the white stuff would start coating it after a while and the strainer would get all clogged up with the white stuff. If I do nothing for 10-14 days (i.e., don't use bleach of vinegar to pour on it, nor try to scrape it), the white growth will coat my entire sink probably. That's about the pace of its growth/advance. I have scraped a lot of it off thus far (sometimes after using bleach and sometimes without it) every few days, but not all of it in one sitting. It's very cumbersome to try to scrape it all. In any case, I think I once scraped it all off - maybe except for a small spot or two - and it STILL came back that one time after about 7-8 days and the build up process began again.

Not sure if it's causing my fungal and yeast infections, which I came back from dermatologist confirming today...I didn't tell her about the white stuff, but since I'll be seeing her in 3 weeks again, I'll ask then...

***see pictures below***

Wrichik Basu said:
A picture would be helpful in this case.
I have four:

2 pics of sink in question (you can see the white stuff and some black dots too that I talked about in my post w/ Borek above)
2 pics of our drying machine (weird black dots began appearing after using the dryer and the exhaust or whatever that thing is with holes is all black too)
--worried my clothes have fungus/mold/mildew and after washing it in the washing machine, it's getting spread in the dryer...

Is this possible?

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  • #25
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Bystander said:
"Lime scale," or soap scum?

Yeah, that's my question. I actually have no idea what it is. I even posited possible white mildew (it exists) and/or white mold (this exists as well).

So, you have:

a.) limescale
b.) soapscum
c.) white mildew
d.) white mold

or a combination of these four (and maybe even black mold, as small black dots have increasingly started form in the sink and a few even in my shower too, which can't be wash away...these are highly resistant black dots that just stay there)...

total mystery at this point...

edit to add:
One other point I'll bring up. Prior to pouring vinegar on the white stuff, the white stuff was quite hard in texture. It started out as a thin layer and would get thicker and thicker and was hard. Even after bleach (which dried it out as mentioned above), it would still grow in a hardened fashion.

After pouring vinegar, the texture was more "slimey" or damp and less hard. If I don't scrape it and leave it, it'll continue to "thicken up," while still remaining kind of "damp" and less hard. ...It's as if vinegar softened this white stuff.
 

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  • #26
Black looks like mold, white looks like a soap scum. Is your water hard?
 
  • #27
Borek said:
Is your water hard?
..., and, do you live in an area where gypsum/sulfate minerals exist/are common? That blue/green patch in the latest picture could be iron/copper sulfate; ferrous sulfate might cook out black in the dryer.
 
  • #28
Borek said:
Black looks like mold, white looks like a soap scum. Is your water hard?

Don't think water is hard, Borek. Did you mean black in the sink is mold or black in the drying machine (those dots and the blackened area around the "exhaust" - or whatever that thing is with the holes) is mold? Or, maybe both? Now that I think about it, if the drying machine has mold, the washing machine likely has it too - although, I don't see black dots like that in the washer.

Also, if the white stuff is soap scum, would you know of any reason why it'd "grow" so fast? As mentioned earlier, if I don't scrape it and/or pour bleach or vinegar on it, it will likely coat half the sink or more (possibly whole sink) within 10-12 days of regular sink usage. That's pretty fast. I wonder if the black dots are mold too if the soap scum + mold make it all this really funky fast growing mixture.

Bystander said:
..., and, do you live in an area where gypsum/sulfate minerals exist/are common? That blue/green patch in the latest picture could be iron/copper sulfate; ferrous sulfate might cook out black in the dryer.
Bystander,
No hard water from what I know of, but I can double-check that with parents.

I'm not sure what gypsum/sulfate is and if it's common in my area. Not sure how to find out.

But, as for the blue/green patch, that's actually a very cheap Irish Spring soap we buy as a family at Costco. I should have explained that the green/blue stuff was pieces of soap that had broken off and I didn't clean from the sink. :wink:

As for ferrous sulfate "cooking out" black in the dryer, I'm not sure what ferrous sulfate is, but the black spots have been recent (past month or so)...I haven't noticed any other changes in my daily habits that would have caused it. I'm worried it's black mold. :frown: Because ...wouldn't that go into the vents of the dryer too and possibly spread to a new dryer if we bought a replacement? A dryer will always be humid too, due to wet clothes in there. Dang, my clothes coming out of the dryer might have mold spores or active mold on them too (although, I think mold will die if it's dry temperatures and there is no water source). Maybe that's why I have been getting skin rashes...*bleep, bleep, bleep*
 
  • #30
kyphysics said:
very cheap Irish Spring soap
I think I've identified the source of your rash.
 
  • #31
Borek said:
This black.

Do you think the black stuff by the "holes" is also mold? I could easily wipe the three big black spots in the dryer middle with white distilled vinegar. But trying to wipe the black stuff on the "grill" with holes seems sketchy and possibly dangerous. ...Do I really want white vinegar near that opening where presumably hot air comes out?

Parents are livid and sister freaking out about not being able to use the dryer until we call professionals in...lots of cursing under the roof.

What a day...tired as hell too. To all those out there with suspected mold problems - TAKE CARE OF IT SOON! Don't wait like me and let that stuff build up. You might get it into your clothes, wash, and dryer - among other places. Maybe if some minor good comes out of this is that it'll be a helpful life lesson for me (I was depressed all night) and possibly others.

Bystander said:
I think I've identified the source of your rash.

maybe...gonna switch to dial and some liquid soap for a while. Thanks for the humor for an otherwise very emotionally upsetting day/night.
 
  • #32
I had a roommate once (he's still around) who tried Irish Spring once. Afterwards skin started peeling off. He had to take a shower to rinse the whatever-is-that! off. If you're getting a rash, don't blame the scum, unless it's the Irish Spring type.

Do you have neighbors on the same water system? If so, do they have the same problem? Does your water smell bad, eg. like hydrogen sulfide? If so, the problem could be a buildup of nearly insoluble sulfides on your porcelain. You can expect sulfide buildup in many geothermal areas, since ground waters can leach them from mineral deposits left by magma/lava in your aquifer. Many sulfides are dark-colored, including black.

If the stuff is to hard to remove with scotchbrite and bleach doesn't stop it, I don't think it's mold.
'Soap scum' is a deposit of calcium or magnesium (heavy metals maybe, see sulfide deposits) salts of the fatty acids in soaps. It's the reason for water softeners. I don't know if these work on sulfide salts, though. You need to ask.

Soap scum, sulfides and carbonates will all dissolve in muriatic acid (hydrochloric acid). Concentrated HCl may be too strong for your porcelain and plumbing. Come to think of it, some drain cleaners are concentrated sulfuric acid. Do the bottles of this stuff in the hardware stores tell you what you can and cannot use the stuff on? If you buy one of these, be very careful with it. It's crude concentrated H2SO4. It will eat through flesh, clothing, flooring, etc. If you dilute it, use a large, separate container and add the acid to the water, to avoid the exothermic reaction causing boiling and splatering you with hot acid.

Otherwise, I have no suggestions. But first thing, chuck the Irish Spring!
 
  • #33
Mark Harder said:
If you're getting a rash, don't blame the scum, unless it's the Irish Spring type.

Alright, guys. You all have convinced me to chuck the Irish Spring. Honestly, I never liked it myself. We always bought it for price - not quality.

Do you have neighbors on the same water system? If so, do they have the same problem? Does your water smell bad, eg. like hydrogen sulfide?
I'll ask my parents to ask around about water quality from neighbors. I'm too busy, atm. But, our water does not smell bad, thankfully. It smells pretty normal.

Soap scum, sulfides and carbonates will all dissolve in muriatic acid (hydrochloric acid). Concentrated HCl may be too strong for your porcelain and plumbing. Come to think of it, some drain cleaners are concentrated sulfuric acid. Do the bottles of this stuff in the hardware stores tell you what you can and cannot use the stuff on? If you buy one of these, be very careful with it. It's crude concentrated H2SO4. It will eat through flesh, clothing, flooring, etc. If you dilute it, use a large, separate container and add the acid to the water, to avoid the exothermic reaction causing boiling and splatering you with hot acid.
In that case, no way. I'll avoid HCI altogether. I know never to use the hardware store plumbing cleaners. I've heard horror stories about them eating through people's pipes. I stick with white distilled vinegar. My mom says she also never uses that stuff and only uses bleach once or twice a month to "cleanse" our pipes.

Lastly, I got an email from my big bro, who said to check out Bio-Clean for the possible pipe/drain build-up:



Amazon described it as:

What is BIO-CLEAN? BIO-CLEAN is a special combination of natural bacteria and enzymes that DIGESTS organic waste found in your plumbing system: grease, hair, soap scum, food particles, paper, cotton ... etc. BIO-CLEAN will not digest or have any effect on inorganic materials such as plastic pipe. It does not product heat, fumes or boiling like chemicals do. BIO-CLEAN is safe for people, plumbing, and the environment. How does BIO-CLEAN work? In nature all animal and vegetable matter is broken down and recycled into plant food by enzymes and bacteria. BIO-CLEAN uses this same principal to biodegrade organic waste that accumulates in your plumbing system. Like all living things, bacteria must "eat" to survive. Fortunately the grease, hair, soap film and organic waste are food for the bacteria in BIO-CLEAN. The enzymes prepare this "food" for the bacteria by breaking down the large molecules into a size the bacteria can "swallow". When mixed with water, BIO-CLEAN immediately goes to work! The enzymes are very fast and start breaking down waste on contact. BIO-CLEAN contains billions of bacteria and as they eat, they double in number every 30 minutes! Unrestricted by gravity, they spread through the entire plumbing system, devouring all the organic waste. Waste accumulates in your pipes causing slow, or even clogged drains. Within days BIO-CLEAN begins to eat through the gunk, restoring drain flow to full capacity. Monthly BIO-CLEAN treatments will keep your drains clean and trouble-free. Authorized by U.S.D.A for use in federally inspected Meat and Poultry Plants.
It's apparently safe enough to eat, as does the guy in the video demonstrates. 800+ positive reviews + Amazon's Choice label. Not sure if this is related to my "white stuff" issue, but the insides of my bathroom and shower pipes have what seems to be the SAME white coating to them. We don't see that white coating in other areas of the house. Maybe this Bio-Clean will help. Sounds way safer than the HCI you mentioned.

Anyhow, appreciate the Irish Spring humor (if it wasn't hyperbole, then WOW, I hope your roomie suffered the least amount possible)! As miserable as this situation is, I was told by my dermatologist to also be super careful with laundry and shower towels. Yeast infections can apparently easily spread from the laundry too! The freakin' week from hell I tell ya! The yeast infection comes several weeks after a fungal one...
 
  • #34
Title topic mentions limescale and bathroom sink. Not reading much past that, there are acidic hard-surface cleaners which may at least, control limescale buildup. Removal is slower. Vinegar can work. Some commercial products contain other acids, example being phosphoric acid. Some such products are given thickener materials to help the formulation stick to some surfaces for a while like if cleaning limescale from a toilet bowl, allowing for a little bit of soak time before wiping. The acid/s will dissolve or help to dissolve the limescale deposits, maybe not very well. The weak acid stuff like products containing acetic or phosphoric, may be safer to use than those containing hydrochloric acid. Not sure by how much. Some rubbing is often necessary. (Use gloves and goggles if you want to do the cleaning with more assurance of safety, regardless of which product you use).

Actually some commercial products give instructions to apply and let set for some time, several seconds or few minutes before wiping, rubbing or rinsing. This gives time for the product to dissolve/start dissolve the hard water scale.
 
  • #35
symbolipoint said:
Vinegar can work.

Yeah, vinegar does work, but I need a sink stopper to plug it up to fill the sink with vinegar and leave it for 30 minutes or more. I'm learning a lot about vinegar these days. Never knew it was a natural "cleaner" and even mold killer that is thankfully inexpensive.

You can get a huge bottle for under $1.00 at any grocery store.
 

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