How To Raise The Alkalinity In A Pool Without Raising The PH

Jessica Stone
by Jessica Stone
Maintaining alkalinity and pH in your swimming pool is of the utmost importance. Raising the alkalinity without affecting the pH can be tricky, but it’s possible with household items like baking soda. Follow along as we explore how you can raise the alkalinity in your pool without affecting pH.

There is much more to owning a pool than enjoying a refreshing dip on hot summer days. To keep your pool water and equipment in tip-top shape you must properly treat your pool by balancing various chemical levels. More specifically, your pool should maintain a pH between 7.2 and 7.8 and an alkalinity level between 80 and 120 ppm.

A pool is considered low-alkaline when the total alkalinity measures below 80 ppm. However, if your pH levels are above 6.8, you will want to balance the alkalinity of your pool without causing a significant increase in your pH levels. So, how can you raise the alkalinity of a pool while keeping the pH in balance?

To raise the alkalinity in your pool without raising the pH, you need to introduce an alkalinity increaser or baking soda. If you want to raise your alkalinity by 10 ppm, try adding between 1 and 2 pounds of sodium bicarbonate (baking soda) per 10,000 gallons of pool water. This will raise the alkalinity of your pool without significantly affecting your pool’s pH.

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Why Raise Pool Alkalinity Levels?

It can be very harmful for both your pool and those who swim in it if the water has a low alkalinity. Levels lower than 80 ppm can cause the walls of your pool to crack, delaminate, or become etched. Whereas, metal surfaces will deteriorate and melt when exposed to such corrosive water conditions. Aside from its effects on the pool itself, an acidic swimming pool is unsafe for swimmers and can cause skin, eye, and nasal irritations.

Even the smallest changes in chemical composition in your pool water can cause severe variations in the pH levels. When your pool’s pH level becomes unbalanced, this phenomenon is referred to as “pH bounce” and can also result in low alkalinity.

When you have low levels of alkalinity, the traditional amount of chlorine that is added to your pool will have no effect. In fact, you’ll have to buy significantly more than the usual amount of chlorine to achieve the same results.

What Causes Low Pool Alkalinity?

The reason your pool may be experiencing low alkalinity levels could be due to one of the following:

  • Evaporation and agitation. Evaporation and agitation of the pool water throughout the season can result in a drop in the total alkalinity level. More specifically, when water evaporates from your pool, it releases both pure water and CO2. The removal of dissolved CO2 from the water will have a direct influence on the total alkalinity, causing it to drop. Consequently, hot water or strongly mixed water (produced by spa pools, jet steams etc.), high heat levels, and bad weather will increase evaporation and decrease alkalinity along with it.
  • Dry acid or muriatic acid. Although useful in treating swimming pools, these chemicals are infamous for reducing the pH concentration of water. If this is the case, you can perform an easy fix by introducing a prescribed dose of the chemical and then testing the alkalinity level after six hours.
  • Drain or backwash. If you drain or backwash your swimming pool, adding freshwater that contains a low alkalinity level will certainly impact its overall pH.

How to Raise Alkalinity In Pool Without Raising pH

When your pool water’s alkalinity is lower than the recommended range, one of the best ways to increase it is by using an “alkalinity increaser.” This product can be purchased from your local pool supply store and boasts the ability to lower total alkalinity (TA) and buffer pH. However, most are unaware of the fact that an alkalinity increaser is just sodium bicarbonate.

Sodium bicarbonate is more commonly known as baking soda. Yes, simple baking soda found in your kitchen can be used to raise your pool’s alkalinity. In fact, you’ll likely be able to save quite a bit of money when you use baking soda over alkalinity increaser. With baking soda, you can enjoy all of the same benefits of packaged alkalinity increaser at a reduced price.

How Much Baking Soda?

One of the potential disadvantages of using baking soda instead of a commercial alkalinity increaser is that baking soda does not come with instructions for use on pools. However, that should not keep you from using it to increase your alkalinity levels.

To calculate the amount of baking soda you want to use, you should first determine how many gallons of water are in your pool. Then, add 1.5 pounds of baking soda for every 10,000 gallons of water. This will increase the pool’s total alkalinity by 10 ppm.

For example, if your pool houses 20,000 gallons of water and your test kit has indicated an alkalinity of 50 ppm, you need to raise your alkalinity by at least 30 ppm. With a pool of 20,000 gallons of water, every three pounds of baking soda will raise the water roughly 10 ppm. Therefore, you need to add about nine pounds of baking soda to a 20,000-gallon pool to increase the alkalinity by 30 ppm. This will put the water in the acceptable alkalinity range of 80 -120ppm.

Once you’ve calculated how much to use, add the baking soda directly into the water. Let it dissolve and allow enough time for it to fully distribute throughout the pool. This will usually take a minimum of twenty minimums with your pump on. Use your test kit to check the levels in the water and add more baking soda as needed.

Baking Soda and pH

When you add baking soda to increase alkalinity in your pool, the normal pH will not be affected. However, if your main goal is to increase the pH versus simply raising alkalinity, try using soda ash. Soda ash, or sodium carbonate, is available at most pool supply stores.

By adding six ounces of soda ash into 10,000 gallons of water, the pH of your pool will be raised roughly 0.2. If you were to use the same amount of baking soda, or sodium carbonate, it will have a negligible effect on your pH, while increasing the alkalinity. Though, it should be noted that soda ash will also raise alkalinity, in addition to pH. The same six ounces of soda ash will raise the alkalinity of your pool roughly 5 ppm.

Follow these rules of thumb:

  • If your goal is to raise only alkalinity in your pool, use baking soda.
  • If you need to raise your pH and alkalinity simultaneously, use soda ash (sodium carbonate)

Regardless of the solution you use, be sure to add it in controlled doses. Test the pool levels first, add, and make adjustments as needed. Introducing too much of either could risk significantly throwing of the levels in your pool.

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Pool pH and Alkalinity Issues

It is not uncommon to have unusual variations in relation to the pH or total alkalinity in your swimming pool. With such a great diversity in water types from region to region, and even within individual communities, achieving a proper balance can be challenging. While it’s always better to have pH and alkalinity levels on the high end than the low end, there are steps you can take to achieve a better balance.

Here are some of the most common issues with pool pH and alkalinity and how to fix them:

  • pH is low, but total alkalinity is normal: Treat your pool with soda ash (sodium carbonate). This will effectively raise the pH and have an insignificant effect on the total alkalinity.
  • pH is low, but total alkalinity is high: Use standard doses of a commercial pH reducer such as Pool Solutions pH Decrease. You can also use soda ash to increase the pH but this will not have any effect on the alkalinity.
  • pH and total alkalinity are both high: Use a standard dose of Pool Solutions pH Decrease. Pour the product into the deep end and let it sit for twenty minutes. Bubbles will indicate that the alkalinity is being eliminated. To prevent damage to your pool, dilute the pH reducer first in a bucket.
  • pH is normal, but total alkalinity is high: Use standard doses of Pool pH Solutions pH decrease. If the pH drops, add soda ash.
  • pH is normal, but total alkalinity is low: Use an alkalinity increaser or baking soda (sodium bicarbonate).
  • pH is high, but total alkalinity is normal: Use standard doses of Pool Solutions pH Decrease to lower pH. If the alkalinity drops, treat with alkalinity increaser or baking soda.
  • pH is high, but total alkalinity is low: Treat with standard doses of Pool Solutions pH Decrease. Then, use an alkalinity increaser or baking soda to increase the alkalinity.

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Jessica Stone
Jessica Stone

Jessica considers herself a home improvement and design enthusiast. She grew up surrounded by constant home improvement projects and owes most of what she knows to helping her dad renovate her childhood home. Being a Los Angeles resident, Jessica spends a lot of her time looking for her next DIY project and sharing her love for home design.

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