# Low water PH and skin **URL:** \ **Category:** Factual Questions\ **Created:** [January 17, 2004, 8:40pm UTC](https://boards.straightdope.com/t/low-water-ph-and-skin/224993 "2004-01-17T20:40:30Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Khadaji](https://avatars.discourse-cdn.com/v4/letter/k/9e8a1a/32.png) [@Khadaji](https://boards.straightdope.com/u/Khadaji)\ **Post date:** [January 17, 2004, 8:40pm UTC](https://boards.straightdope.com/t/low-water-ph-and-skin/224993/1 "2004-01-17T20:40:30Z")
I just checked my hot tub and found the PH to be VERY low. What will that do to my skin? (I’m adding chemicals to increase the pH, I’m just curious what happens if I don’t.) ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [January 17, 2004, 8:45pm UTC](https://boards.straightdope.com/t/low-water-ph-and-skin/224993/2 "2004-01-17T20:45:55Z")
Depends what you mean by “low”. Apparently the secretions of the skin surface are slightly acidic on their own, with a pH of around 4-5.5 (neutral is 7.0, by definition): > [@](#): > > Sweat is a salty, watery solution produced by sweat glands, numerous microscopic channels opening onto the skin surface. As sebum and sweat mix up on the skin surface, they form a protective layer often referred to as the acid mantle . Acid mantle has a particular level of acidity characterized by pH from about 4 to 5.5. A pH of 7 is considered neutral, above 7 is alkaline, and below is acidic. The pH of acid in the human stomach, for example, is usually from 1 to 2, which is highly acidic. The skin, on the other hand, is mildly acidic. In addition to helping protect skin from “the elements” (such as wind or pollutants), acid mantle also inhibits the growth of harmful bacteria and fungi. If acid mantle is disrupted or loses its acidity, the skin becomes more prone to damage and infection. The loss of acid mantle is one of the side-effects of washing the skin with soaps or detergents of moderate or high strength. From [here.](http://www.smartskincare.com/skinbiology/sebum.html) ---
**Author:** ![Vlad\_Igor](https://avatars.discourse-cdn.com/v4/letter/v/7feea3/32.png) [@Vlad\_Igor](https://boards.straightdope.com/u/Vlad_Igor)\ **Post date:** [January 17, 2004, 8:54pm UTC](https://boards.straightdope.com/t/low-water-ph-and-skin/224993/3 "2004-01-17T20:54:00Z")
Oooh, post number one for me. I’m no longer a virgin. 🙂 You don’t say what the pH is/was, but depending on several factors, you might get chemical burns, or nothing at all will happen. What happens not only depends on the pH, but on how much of the acid is present, and how strong it is. You can tolerate the citric acid in a lime you would eat (pH ~ 2.0), but an equal amount of hydrochloric acid would burn your stomach and esophagus. Organic acids (acetic in vinegar, malic in apples) are weaker than mineral acids (HCl, phosphoric, sulfuric, nitric, hydroflouric). That said, I can also take a quart of water, add a drop of hydrocloric acid to it, and it would be a very dilute solution that wouldn’t hurt my skin. The pH will be very low, but there is so little acid present that my skin would not be damaged. Vlad/Igor ---
**Author:** ![Khadaji](https://avatars.discourse-cdn.com/v4/letter/k/9e8a1a/32.png) [@Khadaji](https://boards.straightdope.com/u/Khadaji)\ **Post date:** [January 17, 2004, 9:16pm UTC](https://boards.straightdope.com/t/low-water-ph-and-skin/224993/4 "2004-01-17T21:16:44Z")
The spa test doesn’t show any PH level at all, so it must be REALLY low. Don’t know what the number is though. ---
**Author:** ![Eleusis](https://avatars.discourse-cdn.com/v4/letter/e/f4b2a3/32.png) [@Eleusis](https://boards.straightdope.com/u/Eleusis)\ **Post date:** [January 18, 2004, 12:01am UTC](https://boards.straightdope.com/t/low-water-ph-and-skin/224993/5 "2004-01-18T00:01:47Z")
I don’t have a hot tub, but I do have experience with aquariums and pools, and I would recommend getting a better Ph test. It should only be like $10 or $15 for a decent test where you put, for example, 1ml test water into a test tube, and add the reagent dropwise, counting until the color changes. This will give you a much more accurate and precise measure before you go dumping mass chemicals into it. You may discover that your spa test kit has gone bad and there was never anything really wrong with the water in the first place. Barring that, as it’s only a hottub full of water, I would consider draining the whole thing and starting fresh with a supply of water that within your test range. ---
**Author:** ![Khadaji](https://avatars.discourse-cdn.com/v4/letter/k/9e8a1a/32.png) [@Khadaji](https://boards.straightdope.com/u/Khadaji)\ **Post date:** [January 18, 2004, 12:59am UTC](https://boards.straightdope.com/t/low-water-ph-and-skin/224993/6 "2004-01-18T00:59:36Z")
> [@Eleusis](#): > > I don’t have a hot tub, but I do have experience with aquariums and pools, and I would recommend getting a better Ph test. > > It should only be like $10 or $15 for a decent test where you put, for example, 1ml test water into a test tube, and add the reagent dropwise, counting until the color changes. This will give you a much more accurate and precise measure before you go dumping mass chemicals into it. You may discover that your spa test kit has gone bad and there was never anything really wrong with the water in the first place. > > Barring that, as it’s only a hottub full of water, I would consider draining the whole thing and starting fresh with a supply of water that within your test range. Thanks for the input. Having considered that the test strips might have gone bad, I went and bought a new set of strips with the same results. After adding chems to raise the PH, both sets of strips showed a change. Draining would not help, because adding a large amount of water from my well is what caused the drop in the first place. I would have to bring the new water to proper PH AND let it warm up for hours and try to get the bromine levels up. But what does low PH DO? That is what I want to know. Does my skin dry out? Will I get a rash? There must be a reason that there is a recommended PH level. ---
**Author:** ![Eleusis](https://avatars.discourse-cdn.com/v4/letter/e/f4b2a3/32.png) [@Eleusis](https://boards.straightdope.com/u/Eleusis)\ **Post date:** [January 18, 2004, 1:31am UTC](https://boards.straightdope.com/t/low-water-ph-and-skin/224993/7 "2004-01-18T01:31:31Z")
Water that is too acidic can erode metal parts, seals, pumps, and heaters, and yes it can cause skin irritation which could manifest itself through dryness and rash. I’m not positive if this applies to bromine, but low Ph also causes chlorine to dissipate more quickly than normal.