How To Lower Alkalinity In Hot Tub (Without Affecting pH)

Do you know how to lower alkalinity in hot tub without affecting pH? If you don’t, then this detailed guide is here to show you exactly how to do so safely.

Installing a hot tub in your house is one of the best things that you can do if you would like to relax after a tiring day at work. Hot tubs allow you to recover your strength and also massage your muscles gently.

The jets help with massaging the muscles, and this is the ideal way for a person to unwind after a stressful day at work.

However, if you talk to any hot tub owner, they will tell you that these things must be maintained properly if you want to make the best use of them. Issues with your hot tub are usually caused due to lack of maintenance.

For instance, one of the most important things that you will need to care for is the alkalinity in the hot tub. The composition of chemicals in the water needs to be appropriately balanced because that could affect how the water feels.

There are several things you need to understand about the alkalinity in the water and how to balance it. But, before we get started, it’s important to focus on the pros and cons.

What’s the Harm with High Alkalinity?

There are several reasons why it is important for you to maintain a balance between the alkalinity in your hot tub. Ideally, most experts recommend that the alkalinity in the hot tub should not be higher than 7.8 pH, but it should also not be below 7.2 pH.

If the alkalinity of the water rises above a certain level, it will create an imbalance in the pH value. This ultimately increases the amount of calcium in the water. Basically, you will find yourself sitting in a pool of hard water.

If you don’t know, hard water is essentially water that has a higher mineral content in it. When the alkalinity rises, it probably means that the calcium levels in the water are higher than they should be.

This could create a myriad of problems for your hot tub. It could, for instance, cause scaling, which could cause the filters to clog up.

More importantly, the water might become cloudy as well, and that’s really not something that you want when you are sitting in the hot tub with a few people.

It’s important to understand that scaling in the pipes and jets could be harmful for your hot tub in the long run. It could prevent the jets from firing water freely and can eventually cause the pipes to choke up.

The scaling will reduce the amount of free space available for the water to flow through the pipes as well, thus reducing the pressure.

More importantly, if you use bromine or chlorine in the water as a sanitizer, hard water neutralizes it to an extent where it’s not that effective anymore.

If you have sensitive skin, that could be a problem as well, because hard water may cause redness and itching over time. Needless to say, it’s something that you will want to avoid.

What If the Alkalinity Is Too Low?

As you can see, the harmful effects of high alkalinity cannot be ignored. But, why not just keep the alkalinity low then? As it happens, low alkalinity in the hot tub is also a major problem.

If the alkalinity falls below a certain level, it could cause the water to turn acidic. Essentially, you will be swimming in corrosive water, and this means that the water will cause serious harm to any metallic surface.

Ultimately, it could cause the lining in the hot tub to tear, and all the internal pipes will start to rust as well. As you can imagine, water with low alkalinity is a strict no-no for your hot tub and could lead to irreversible damage.

Thus, we are left with the best way forward: maintaining a pH balance. It’s one of the main reasons why you need to monitor the water in your hot tub carefully to make sure that it remains slightly alkaline, but not by all that much.

Revising Acids and Bases

Before giving tips on how to lower the alkalinity levels in the hot tub, it is important to understand the basics so that you know exactly what you are doing. Obviously, you have studied all of this back in high school, but it’s still worth a revisit.

The pH value is basically an indicator of just how basic or acidic a liquid really is. Acids have pH values that lie below pH 7, whereas bases have a pH value above pH 7. At pH 7, the solution is considered to be neutral.

For instance, the pH value of coffee is between 6 and 4.5, which means it’s slightly acidic. On the other hand, citrus juices and even lemon has a pH value that’s between two and three, which makes it incredibly acidic.

The acid in your stomach, known as hydrochloric acid, has a pH value between 1 and 2, which makes it one of the most acidic solutions you will find.

On the other end of the spectrum, you have bleach. Bleach has a pH value just above 13, which means it is a basic solution. Now that you understand the basics, let’s talk about alkalinity and PH values.

Alkalinity and pH Values

A vast majority of the people often get confused when using terms like “pH” and “alkalinity,” so it’s important to clarify that the two are slightly different. Too many people believe that alkalinity and pH values are similar, but that’s not true.

If the water in your hot tub has a pH value that’s higher than 7, the water’s basic. However, that doesn’t always mean that the water has a higher amount of alkalinity.

In essence, alkalinity of the water simply highlights the quantity of acid that the water is able to neutralize. Alkali is added into the solution to neutralize an acid.

The total alkalinity of the water in your hot tub simply highlights the amount of alkaline substance that was dissolved in the water supply. Ideally, you will want the alkalinity in your hot tub to be between 80 and 120 parts per million.

If the amount of alkalinity in your hot tub is ideal, it is capable of countering the chances caused by the fluctuation in the pH value of the water. This also prevents the harmful damage caused to your hot tub.

Needless to say, it’s very important for you to make sure that your hot tub has the right amount of alkalinity. While the relationship between alkalinity and pH values is close, you should know by now that they are not similar.

How to Test the Water

Before you can decide to add more or less alkaline substances into your hot tub’s water, it’s important to test it properly using some strips.

There are testing kits that are readily available, so you can use those to get an accurate idea about the pH value of your water. When you buy a testing kit, just go through the instructions on the back to get a better idea of what you need to do.

You can check the alkalinity to get a better idea about where it stands. To recap, the ideal alkalinity should be between 80 and 120 ppm. A common mistake that many people make is that they forget the testing after a while.

Even if the alkalinity is perfect, you need to test it from time to time to make sure that it stays that way. Consistent monitoring is important if you want to make sure that the alkalinity remains the same.

How To Lower Alkalinity In Hot Tub Without Affecting pH

If the alkalinity of your water is higher than 120 ppm, you will want to lower it. Ideally, you should keep it balanced at 100 ppm. One of the best ways to lower the alkalinity is to add sodium bisulfate.

But measuring the quantity depending on the volume of water is also equally important. This is easy to calculate; you first need to figure out the volume of water in your hot tub.

You can refer to the owner’s manual or check the make and model of your hot tub online to find out the volume of water it can hold.

To lower the alkalinity of a thousand gallons of water by a mere 10 ppm, you will want to add at least 3.5 oz of sodium bisulfate. By the same calculations, if you want to lower the alkalinity of 600 gallons of water, you will want to add around two ounces of sodium bisulfate.

Once you add the sodium bisulfate, just let the water circulate before shutting off the jets. Leave the tub overnight and then check it in the morning to determine whether the alkalinity is fine.

Alternatively, you can raise the alkalinity by adding sodium bicarbonate, or baking soda. To raise the alkalinity of 500 gallons of water by 10 ppm, just add 1.125 oz of sodium bicarb. Let it circulate before leaving it overnight and checking it again.