What Causes Low pH in Pools

The pH level is the measure of how acidic or alkaline the water is. On a scale ranging from zero (highly acidic) to fourteen (highly alkaline), the ideal pH of pool water is between 7.2 and 7.8. There are plenty of things that can lower the pH of your swimming pool. What Causes Low pH in Pools?

The main culprits are:

  • Chlorine tablets with stabilizer (CYA)-2.9 pH
  • Rain 5–5.5 pH
  • Children’s urine 6.0 pH
  • Shampoos 4.5-6.0.pH
  • Beer 4.00–5.00.& Ales 3.00–6.00 pH
  • Coffee 4.85-5.1 pH & Soda 2.5 to 3.5 pH
  • Leaves that fall are below 6 pH
  • Skin products & Cleansers: pH 4.5–7. Toners: pH 5–7. Sunscreens: pH 5–7.5.

Although the common way for your swimming pool to decrease its pH is by chemicals or chemical loss there are many things that enter the pool water besides people but they are m,ost likely carried in by the same people who enter the pool that day

What Causes Low pH in Pools


The most common cause of a consistently low pH level in pools is using chlorine tablets or stabilized forms of chlorine. These have a very low pH level and depending on how much cyanuric acid is added decrease the pH.

A chlorine tablet has two side effects that most pool owners don’t realize: It has a pH of 2.9 but more importantly, it lowers Total Alkalinity (TA). It is 52% cyanuric acid or conditioner/stabilizer by weight and each one increases the cyanuric acid level (CYA) in your pool water.

CYA is acidic and it keeps on lowering pH the entire time it is dissolving. Metal Free is also somewhat acidic. Sequestrant slowly decays in the pool. That is why regular maintenance doses are required


Reasons for Lower Water pH


Changes in the pH of pool water can be caused by many factors but one of the most significant causes is the sanitizer used. Since sanitizer is the most frequently added chemical in pools, it can have a powerful impact on pH and overall water quality.

Of the sanitizers typically used in pools, chlorine is the most common. Chlorine comes in a variety of forms and varies widely in pH. For example, most tableted forms of chlorine have a very low pH and will tend to lower pH over time, while liquid chlorine is very high in pH and do the opposite will raise pH values.

Salt is also very alkaline and will require frequent additions of acid to maintain the proper pH and overall water balance.

Changes in pH due to sanitizers or other factors can be minimized and controlled by the proper maintenance of the next chemical factor, total alkalinity. Lowering a pool’s pH naturally can be done in four ways: installing a distilled water system to pump in water, cleaning your pool on a regular basis, leaving it alone, and letting the pH level come down on its own as minerals build up, or installing a pool heater. 

Low pH Low Alkalinity in Pool: Raise pH In Swimming Pool Water


Acidic rainfall, heavy leaf debris, and dirt/mulch blowing in the pool can also lower the pH level.Outdoor Patio Shower with Foot Washer 78" | eBay

Natural rainwater has a pH of 5 – 5.5, so it is naturally acidic. A substantial amount of rainfall can alter the pH of pool water to become more acidic.

If it has been raining heavily and your pool is uncovered, the pool water may experience a drop in pH levels. This occurs because rainwater is slightly acidic, especially in areas where there are industries, and can alter the pool’s chemical balance.

 The average urine sample for children tests at about 6.0, but typical urine pH may range from 4.5–8.0. The higher the number of kids in your pool the more chance some kids will pee in it and some grownup kids.

Shampoos formulated at low pH can help protect the hair’s cuticle layer and the scalp’s microbiome. That’s because low-pH shampoos have the same pH range for the hair and the scalp: run from 4.5 to 6.0. pH. Plus, pH values can vary depending on the product’s ingredients.

Not only are sodas extremely high in sugar content, but they also have an extremely low, or acidic, pH. Most sodas have a pH in the range of 2.5 to 3.5 on the pH scale. This work found the pH measurements for all coffee samples tested to be comparable, ranging between 4.85 to 5.13.

Beer is thus slightly acidic, with 100% barley malt lager beers having a pH in the range of 4.00–5.00. Ales vary a little more, typically pH 3.00–6.00. Most leaves are slightly acidic when they fall, with a pH below 6. Yea, I’ve seen a few beers and soda go into the pool.


What causes high pH in Pools?

  • Sudden rise in water temperature
  • Water features that take water out of the pool aerating it
  • Release of Carbon Dioxide(CO2)
  • Swimmers using sunblock or lotions
  • Liquid bleach, such as Clorox has a pH level of around 11-13
  • New pool surface and walls leaching in H2O
  •  Off-gassing
  • Use of Algaecides ………………………………………………………………….. Read more

pH of Skin Care Products List


Nexxus Therappe is an excellent and popular shampoo for dry, brittle hair, and for people who struggle with hair breakage due to its patented ProteinFusion formula is 4.2-6.0 pH The pool’s pH levels might also drop after hosting a large pool party.

Dissolved bodily fluids can lower pH levels, so if you have had a lot of swimmers in your pool recently, this could be the culprit or maybe one or more of these multiplied by the number of people in your pool.

  • Cleansers: pH 4.5–7.
  • Toners: pH 5–7.
  • Sunscreens: pH 5–7.5.
  • AHA and BHA Exfoliants: pH 3.2–3.9, with any reading between 3 and 4 considered most effective.
  • Moisturizers: pH 5–7.
  • Serums: pH 4–6.
  • Vitamin C (ascorbic acid) products: pH 2.6–3.2.
  • Retinol products: pH 4–6.6

Pool Showers: Help Raise Lower pH in a Pool-Control Low Pool pH


You should always shower before going swimming. If you don’t, fecal matter and other nasty contaminants can easily start mixing into the pool water.

Something that might surprise people is we all have small amounts of fecal matter on our bodies on most days. On average, the U.S. Center for Disease Control and Prevention estimates that people have 0.14 grams of fecal matter in their bodies.  So you might want to avoid swallowing pool water. It can make you very very sick.

Swimmers showering can fight off a variety of Recreational Waterborne Illnesses(RWI). This prevents common causes of diarrhea, skin infections, and eye infections.

Using pool disinfectants like chlorine products protects us and prevents us from picking up waterborne germs. Organic compounds that mix with chlorine are found in deodorants, soaps, moisturizers, sweat, detergents, and fecal matter.

Raise Pool pH 


When organic compounds are mixed with chlorine-treated water, by-products are created. These are gases called Chloramines. Chloramines lead to that unusual chlorine smell that we think is a sign of a clean pool. This is what causes low pH and low total alkalinity in a pool.

Low pH water and low alkalinity will cause irritated eyes and etching and deterioration of plaster, grout, stone, concrete, and tiling. Any vinyl surfaces will also become brittle, which increases the risk of cracks and tears. All of these dissolved minerals will hold in the solution of your pool water; which can result in staining and cloudy pool water.

They’re not. The smell of chloramine are problems sign that the pool’s ph is not being maintained to the highest quality and the pH is inadequate. A well-managed pool should have little to no chlorine odor for environmental health and alkalinity pool pH problems.

The pool’s low acidic pool water can be adjusted with baking soda and soda ash baking soda aka sodium bicarbonate are two solutions you can add to the lower pool pH water to raise the pool’s pH.

You can add sodium carbonate or soda ash directly to the pool or spa to raise pH levels whatever the cause. For the best results, walk around the edge while you dump the chemicals to distribute them evenly. Add 1.5 pounds of baking soda per 10,000 gallons of water.

This pH problem makes a strong case for installing a pool shower at the swimming pool. Shower before you get into the water and Shower when you get out. Problem solved!


What are the Signs of Low pH in a Pool?

  • Cause Chlorine By-Products(Chloramine)
  • Impact chlorine effectiveness
  • Eye irritation
  • Cause etching of plaster, grout, stone, concrete, & tiling in concrete pools.
  • Vinyl surfaces will also become brittle, risk of cracks & tares.
  • This can result in staining & cloudy pool H2O
  • Cause Irritated skin .……………………………………………………………………………………… Read more


JimGalloway Author/Editor


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