How To Lower The Alkalinity In Your Pool
In this guide you’re going to learn how to lower the alkalinity in your pool .
To lower the alkalinity in your pool, try using a strong acid like muriatic acid, sodium bisulfate, or sulfuric acid all of which will lower the alkalinity.
If your pool water is a little murky or your pool filters seem to be plugged with calcium deposits, then your pool may be suffering from high alkalinity levels.
In today’s post, you’re going to learn all about water alkalinity, what causes your pool alkalinity to get too high, and how to lower it.
Let’s dive in!
Testing The Alkalinity Level Of Your Pool Water
If you re unsure if the alkalinity level of your pool water is much too high, then youll want to invest in a pool testing kit. These kits are usually affordable and typically can be purchased at most home improvement stores.
One popular brand is the Taylor Complete FAS-DPD Chlorine test kit. It costs about $60 and can be used multiple times. This is just one of the several brands sold today. Theres many more to choose from. However, many people warn against using test strips due to their inaccuracy. Its essential that you spend the money and get a good kit, and Taylor makes very accurate kits recommended by many professionals.
The instructions listed below are based on using the Taylor Complete FAS-DPD Chlorine test kit. If youre using a different brand, follow the steps listed below with the instructions provided in your kit. Most kits are used about the same, so there shouldnt be a huge difference.
Summary Of Key Points
- Total alkalinity should only be lowered when it causes a significant rise in pH levels, or when it causes calcium scaling through CSI.
- To lower pH and total alkalinity, use a strong acid such as muriatic acid, sulfuric acid, or sodium bisulfate, all of which lower both pH and TA, but at different rates.
- You need to use an accurate water test kit that can give you correct readings. If possible, find software that can help you get exact amounts of dry acid to add into the water.
- This process may take longer than anticipated, depending on how high pH or total alkalinity is and how low you need to bring them down before the aeration process begins. However, you can always use an air compressor or any other aerator to accelerate the process.
- If you have achieved the ideal reading for total alkalinity but the pH is scaling up because the process of aeration has not yet ceased, you can use borate to keep the pH stable. The recommended level for pH is around 7.4 or 7.6.
This article is accurate and true to the best of the authorâs knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.
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Take Readings Again After 24 Hours
The next day, a full 24 hours since I started my test, the total alkalinity had gone down to 120 ppm. This is not the 100 ppm target value I set, but I was still impressed since 120 ppm is already within the recommended value for a standard swimming pool.
On the other hand, pH was lower, reading 7.1. I didn’t worry too much about this because according to my digital pool water test kit and pool calculator, the lowest it pH can go is 6.8 and still be okay and non-destructive. Plus, the aeration process wasn’t finished.
Since both chemicals were within a reasonable range, all was fine for me. So I waited to take my next reading in the evening, approximately 5 to 6 hours later. At that time, TA was ranging at 106 ppm, and pH had dropped to 6.9.
This means that total alkalinity was inching closer to my target value of 100, despite pH going down.
S For Lowering Alkalinity In Pool
Regardless of which method you use, you have to test the levels before you start and after you finish. Also, before you begin handling any of these pool chemicals, you should wear protective gear such as safety goggles and acid-resistant gloves.
Here are step by step directions for lowering alkalinity using the two most common methods: dry acid and muriatic acid.
Method 1: Using Dry Acid
Dry acid or sodium bisulfate comes in a granular form, and it will be safer to handle than muriatic acid. However, it also costs much more.
Step 1 Test the Alkalinity Level
You need to test the alkalinity to determine the actual level before adding any chemical to the water. Here digital testers will give you the most accurate results, but test strips can also be helpful if you want an inexpensive option.
Also, remember to test the levels several times at least a few hours apart to ensure you get accurate results. Alkalinity levels often go down on their own, so testing several times will help you determine whether any intervention is necessary.
Step 2 Determine How Much Dry Acid to Use
Next, you should determine how much dry acid to use. The actual alkalinity level in your pool water and the directions on the dry acid packaging should guide you here. You need to add just the right amount to get to the 80 and 120 ppm optimal level.
Step 3 Mix Dry Acid with Water
Most manufacturers will provide specific dry acid to water ratios, and so you should stick with them if they are available.
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What Causes Low Pool Alkalinity
The following points are to be considered as culprits for pool alkalinity
- Use of dry acid or muriatic acid. These chemicals, although useful in treating swimming pool water, are notorious for reducing pH concentration in water. A way of fixing this is by applying only a prescribed dose of the chemical in case there is a need to lower your pools pH. Then you can test your pools alkalinity level after 6 hours.
- It probably rained hard. Rainwater might be low in alkaline levels, and when it rains hard, your pool may become flooded, and this will affect the average alkalinity of your pool.
- If you drain or backwash your pool, adding freshwater with a low alkalinity level is bound to deplete the overall pH of your pool.
Test The Total Alkalinity In Your Pool
With the use of a pool test kit, get a sample of the water with the use of a water collector. The water must be taken from 12-18 inches deep.
Then, add the reagents into the water. After adding the reagents, make sure to add a small amount of chlorine neutralizer. This is one way to get the correct reading of the total alkalinity in your pool.
Chlorine levels can affect the level of pH in your pool. Cover the pool test kit, then shake it. If you are using pool test kits with test strips, wait for 30 seconds before dipping the test strips into the water collector.
Compare the color in your kit with the kits chart. If you have a pH level of 7.2-7.6 on the litmus scale, it means that your total alkalinity is balanced.
However, if the amount is lower than 7.2, you need to increase the alkalinity in your pool. Moreover, if the alkalinity is more than 7.6, you need to decrease the alkalinity
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What Is Pool Water Alkalinity
Not to worry.
Water alkalinity is a measure of how much acid it can neutralize.
In the swimming pool, it acts as sort of a buffer to stabilize pH levels, which is important to prevent scaling and other pool problems.
Pool alkalinity is measured at total alkalinity and it is simply the amount of alkaline substances in the water.
In a swimming pool, the bicarbonate alkalinity is the substance that needs to be regulated.
It should be between 80 and 120 ppm .
Use A Bucket To Lower Alkalinity More Than Ph
You cant lower Alkalinity without lowering pH, just as you cant raise Alkalinity without raising pH, but there is a method to favor one over the other. Use a bucket to raise or lower Alkalinity more than pH.
The pool Alkalinity Bucket Trick is really just a play on the maxim, to lower pH more walk your acid, to lower alkalinity more pool your acid, and it results in a more rapid exchange of hydro-carbons, in a smaller area with low circulation.
One more tip for correct pH and alkalinity testing, a titrant test is much more accurate than test strips. I always recommend the Taylor K-2005, but if the $75 price tag is too much, take a look at the $20 Taylor Troubleshooter, for a very reliable titrant pool pH and Alkalinity test kit.
If you have any other questions about pool pH or alkalinity chemicals that we didnt cover, or need to see our pH and alkalinity dosage charts or for any specific pH and alkalinity problems you are having, please leave me a comment below! I answer them personally!
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How To Lower Alkalinity And Ph
Natural aeration is highly recommended, but if you need faster results, at the end of this article I have included a list of equipment that will help speed up the process and instructions for how to use it. Extra care must be taken to avoid over-aeration if you decide to use aerators because over-aeration raises the pH levels and lowers the calcium carbonate levels beyond recommended levels, which can cause significant damage to the pool.
Problems/effects Of High Alkalinity:
- Cloudy Water – Excess alkalinity may increase calcium and magnesium hardness, which in turn will cause the water to be cloudy.
- Pool surface staining – The high pH may also result in pool surface staining. Calcium and magnesium minerals from the water frequently stain pool surfaces if alkalinity is high.
- pH bounce – High total alkalinity can increase the frequency of pH bounce . In cases with extremely high alkalinity , a pH swing of more than 0.4 units per day may be observed when either calcium or cyanuric acid drops. This causes an increase in demand for chlorine, so more chlorine is added by the pool owner…but this just causes even greater increases in pH!
- Chlorine loss – The high pH caused by excess alkalinity causes chlorine to be converted to forms that are less effective as a sanitizer. This causes the owner to use more chlorine, which increases the problem even more!
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Lowering Total Alkalinity Without A Ph Change
chem geek said:Procedures for Lowering TAThere is also the acid column or slug method myth that was discredited in this paper. It’s not that the method doesn’t work at all, since the amount of TA lowering is solely dependent on the amount of acid you add and not how you add it, but rather that it is not the safest method nor the most efficient . The efficient procedure for lowering TA is described in this post and in the Pool School Lower Total Alkalinity procedure. The procedure works because the outgassing of carbon dioxide is accelerated at lower pH as shown in this chart.The handbook only says to add acid to lower the TA and does not discuss more efficient ways of lowering it via lowering the pH and increasing aeration .
Testing And Lowering Total Alkalinity
Test your pool water for total alkalinity weekly. Dip a test strip about 18 inches below the water surface, following the manufacturer’s instructions, then remove. Compare the test result color against the test kit guide to determine the TA level. Concrete and concrete-related pools require a TA level of 80 to 120 parts per million , while levels of 125 to 170 ppm are recommended for painted, fiberglass and vinyl pools.
Measure your choice of TA-lowering chemical, either sodium bisulfate or muriatic acid. Read the product instructions carefully before treating the pool water different manufacturers suggest different treatment procedures or varying amounts of product. A typical treatment consists of either 24 ounces of sodium bisulfate or 20 fluid ounces of muriatic acid for 10,000 gallons. This is enough to lower the TA by 10 ppm. Use a plastic measuring cup, if necessary, and pour into a plastic bucket to prevent a chemical reaction.
Broadcast the muriatic acid or sodium bisulfate in the deep end of the pool. For smaller pools without a depth change, select a given end where a water return distributes water. Lay across the pool deck or bend over an aboveground pool to position yourself close to, but not touching, the water. Pour the alkalinity decreaser into the water immediately in front of the water return, which encourages the chemical to quickly disperse through the water.
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The Role Of Total Alkalinity In Water Chemistry
If youre a pool operator, you probably already know that pH can fluctuate up and down. And when it does, the pool is constantly fighting against you. Having the right level of total alkalinity is a good thing, because it helps to keep the pH stabilized. A simple way to think about alkalinity is that it insulates pH from changing too easily, especially going down.
Technically, alkalinity buffers pH by either releasing or absorbing a Hydrogen ion as needed. So when acid is added, carbonate ions can absorb Hydrogen to create bicarbonate ions. This is an equilibrium, just like pH, so it can go the other way too. The equilibrium looks like this:
HCO3- + H+ H2CO3
Since CO2 controls the pH of the water, you can either add CO2 directly to lower pH, or you can use acid to convert bicarbonate alkalinity into carbonic acid , which is just dissolved CO2: .
You could add several pounds of 8.3pH Sodium Bicarb and make the same pH impact if you added a much smaller amount of 11.6 pH soda ash. But the total alkalinity would be higher for the Sodium Bicarb, because theres simply more of it in the water.
Lowering Total Alkalinity Without Affecting Ph
Can the Acid Slug Lower Total Alkalinity Without Affecting pH?
The ability to control whether you lower Total Alkalinity or pH by the method in which a dose of acid is added to a swimming pool would certainly be of great value to the Pool Operators.
To lower Total Alkalinity drastically with only a slight effect on pH, simply take your dose of acid and pour it slowly into one spot in the deep end of the pool. Youll actually see the bubbles forming around where the slug is added that is, the bicarb burning off and bubbling up. If you wish to lower the pH without also reducing the Total Alkalinity, simply pour the dose of muriatic acid about the pool.
This would all be wonderful if it was only accurate. Still, just like the mythological Chlorine Lock, folkloric tales within the swimming pool industry do persist. But, Lowering Total Alkalinity Without Affecting pH?
When hydrochloric acid is added to water, the molecules disassociate into both hydrogen ions and chloride ions . This happens, no matter how it is added. To keep it simple, when you increase the number of hydrogen ions in a solution, the water becomes increasingly acidic. Remember, pH stands for Potenz Hydrogen, which can be interpreted from the original German to Hydrogen Concentration. So, if adding acid to water increases the hydrogen ion concentration no matter how you add it and pH is the Hydrogen Concentration Hmmm?
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Is It Safe To Swim In High Or Low Ph Or Alkalinity
Maybe yes, maybe no. Your pool water pH and alkalinity can affect disinfection by chlorine. Chlorine is very slow to react at high pH levels, and can be over 50% inactive at pH levels over 8.2. However, even with high pH a pool could still be sanitary with good levels of free chlorine, and clear water from effective filtration.