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How To Raise Alkalinity In Your Pool (2 Proven Methods)

Total alkalinity (TA) keeps your pool’s pH level balanced by absorbing fluctuations in the water chemistry. It’s basically a pH buffer.

The optimal range for pool alkalinity is between 80 and 120 parts per million, so anything below 80 ppm will leave your pH especially vulnerable.

So, what causes this, what happens as a result, and how do you raise alkalinity in your pool the right way? Let’s discuss.

Why You Have Low Alkalinity

The total alkalinity of pool water is directly correlated to the pH level of the water, inextricably linked like peanut butter and jam. When the pH level goes down, so goes the alkalinity, tilting the water from a neutral state to an acidic one.

If this is happening in your pool, it’s probably due to one of the following reasons:

The first one is rain. Rainwater is a common offender in the lowering of a pool’s pH level because it has a slightly acidic pH level of 5.

When it falls, it picks up atmospheric pollutants like sulfates, phosphates, and nitrates, becoming even more acidic. This acidity is then injected into the water, causing a drop in pH and alkalinity.

Pollutants from people in the pool is another reason for low alkalinity. A person’s sweat or urine can alter the pool water chemistry. So, for everyone’s sake, try not to pee in the swimming pool, m’kay?

Finally, chlorine tablets can be another reason for falling alkalinity. While they raise pH during shocking, the tablets themselves have a low pH level. As a result, using them will diminish your water’s alkalinity level .

Why Low Alkalinity Is Bad News

When a pool’s alkalinity measures below 80 ppm it can cause unwanted side effects, including:

  • Fluctuating pH levels. Wild swings in the water’s pH will occur if the alkalinity is low. This is also known as pH bounce, and is the result of the pool water not having an adequate buffer, aka the proper alkalinity level. When pH bounce occurs, you’ll see it swing from being acidic one moment, and alkaline the next.
  • It can cause irritation to swimmers. When alkalinity is low, the pool water becomes acidic and makes it an irritant for swimmers that are exposed to it. Burning eyes and itchy skin will result, and some people can also suffer respiratory issues.
  • Green pool water. While a green pool is usually the result of algae growing in the pool, the conditions must first be created for that algae to bloom. Low alkalinity creates those conditions, and you’ll have to spend a significant amount of time destroying all traces of algae, and bring the water back into balance.
  • Etching and staining of surfaces. Low alkalinity pool water is highly destructive to your pool surface. Etching, delamination, and cracks can all appear in plaster finishes, and vinyl liners can become stiff and brittle as a result. Staining of finishes is also common.
  • Corrosion. Metal surfaces and pool equipment can be severely damaged as low alkalinity water eats away at them. These can be things like ladders, handrails, pool lights, and heat exchangers. Replacing these things can cost a pretty penny and is obviously something you want to avoid.

How To Raise Alkalinity In A Pool

Now that you know how low TA negatively affects your pool, raising it should be a top priority.

There’s 2 ways you can do this, both starting with testing the water so you know how high you’ll need to raise the alkalinity level.

Method #1: Use Baking Soda

There are fancy products on the market under the moniker “Alkalinity Increaser” or “Alkalinity Up” that can raise the water’s alkalinity level fairly quickly. 

In reality though, they only have one ingredient – sodium bicarbonate, more commonly known as baking soda.

The upsides to using baking soda are that it’s extremely safe, easy to work with, can be poured directly into the pool, and any grocery store sells it. Regular baking soda is also cheaper than Alkalinity Increaser, so you can save some money doing it this way as well.

Baking soda is the preferred method as it will raise total alkalinity while minimally affecting the pH level of the water.

Here’s how to use it:

  1. Test your pool water using a digital test kit or test strips to determine how much you need to raise the total alkalinity of the water.
  2. A general guideline is adding 1.5 lbs. of baking soda per 10,000 gallons of water to raise the TA by 10 ppm. Remember, you’re aiming for a level of at least 80 ppm.
  3. Wear rubber gloves and goggles for protection (baking soda in the eyes is not a fun time).
  4. After you’ve measured out how much you think you’ll need, you can dilute it or add it directly to the pool.
  5. Walking around the perimeter of the pool, pour in half or three quarters of the measured amount. We recommend adding it in stages, so that you don’t overdo it and potentially spike the TA and pH levels.
  6. Wait 6 hours for the jets to fully circulate the baking soda in the pool.  
  7. Retest the water to determine the new TA level. If it’s still low, repeat the process until the desired level is reached.

Method #2: Use Soda Ash

Soda ash, otherwise known as sodium carbonate, is the other ingredient you can raise the water’s alkalinity level. 

While it does the same job as baking soda, soda ash tends to drastically raise both the TA and pH level, which can cause issues if the pH level doesn’t need to be increased.

Here’s how to use soda ash to raise TA:

  1. Test your pool water using a digital test kit or test strips to determine how much you need to raise the water’s TA level.
  2. A general guideline is adding 6 oz. of soda ash per 10,000 gallons of water to raise the TA by 5 ppm. This amount will also raise the pH level by 0.2.
  3. Wear rubber gloves and goggles for protection.
  4. After you’ve measured how much you think you’ll need, you can dilute it or add it directly to the pool. Walk around the perimeter of the pool and pour it in.
  5. Wait a few hours for the jets to fully circulate the soda ash. 
  6. Retest the water to determine the new TA level. If it’s still low, repeat the process until the desired level is reached.

How To Bring pH Back Down

Balancing your pool can be tricky, and you may find after raising the alkalinity that the pH level is now too high.

You can lower the pH by adding a measured amount of muriatic acid (hydrochloric acid) or dry acid (sodium bisulfate) to your pool water. Sulfuric acid is another option, but it significantly raises your TDS levels too.

Muriatic acid is highly corrosive so always make sure you take extreme safety precautions when using it. Instructions on the bottle will help you with the correct dosage for your pool, and adding it is simple using a 10:1 solution that’s diluted with water.

Dry acid is a milder option that comes in granular or powder form, which makes it slightly easier to work with. It’s also more expensive and just as dangerous if mishandled. Once again, it’s best to follow the instructions on the label.

Be aware that lowering pH will also ultimately lower alkalinity using the methods described above. In that case, you can use baking soda to raise alkalinity with minimal effect on pH.

Finally, as usual, use water testing methods before and after to lower the pH to between 7.4 and 7.6, the ideal range for neutral pool water.

Pick Your Poison

Whether it’s through baking soda, or soda ash, raising alkalinity in a pool is easy to do. 

By testing and paying attention to the correct dosage amount, you can have your swimming pool water rebalanced and back to a swimmable condition within a matter of hours.

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