Hot tub owners are regularly faced with different issues. Most of the time, these issues center around the right chemical balance. These issues always lead them to find what the best solutions to those problems might be. One that tops this list is the issue of alkalinity and whether baking soda can be used to lower it.
The answer to that question is no, as baking soda itself is an alkaline substance. Therefore, adding baking soda to your tub’s water will only raise the alkalinity levels.
Follow me in this article as I delve deep into these alkalinity issues and other alternatives you could make use of.
How do I bring the alkalinity down in my hot tub?
Before we go into this, it will be good to understand what alkalinity actually is. People tend to confuse these terms: alkalinity and pH. Though closely related, they are not the same. pH simply refers to how acidic or basic an aqueous solution is.
It gives us a measure of the hydrogen ion concentration in a solution. Alkalinity, on the other hand, simply refers to how much acidity water can neutralize. It gives us a measure of the buffering power of a solution.
The total alkalinity is now a measure of how much an alkaline substance has been dissolved in water. It is measured in parts per million.
However, alkalinity affects pH. When alkalinity goes above the average, pH increases. In the same way, when alkalinity decreases, pH decreases as well. The recommended total alkalinity is between 80 and 120 parts per million.
When it goes above this value, you will need to take steps to reduce it. Your aim is to bring it to somewhere around 100 parts per million.
These are the steps to take.
- Test the water: Always ensure to test the water before going ahead. You can never be too sure. Like mentioned above, the ideal range is between 80 and 120 ppm.
- Choose your chemicals: The most popular choices for lowering alkalinity are muriatic acid( hydrochloric acid) and sodium bisulfate (dry acid). You can also make use of any other alkalinity decrease that is found in stores around you. The working principle is that the acid reacts with the bicarbonates in water, and in this way, alkalinity is reduced.
- Measure out the dosage: Generally, to reduce total alkalinity by 10 parts per million, you will need to add 725.75g of sodium bisulfate or 1.23 liters of muriatic acid to every 38,000 liters of water. This proportion can then be adjusted to fit your hot tub.
- Mix the chemical with water: Now, in a chemical-resistant bucket, mix this dosage of chemical with a small amount of water. Allow it to dissolve. Remember that you pour acid into water, and not vice versa. The reason for this is that water is a better heat sink than acid.
- Turn on the hot tub: Turn on the pumps and ensure that the filters are running. Now, gradually pour in the acid-water mixture. You must do it this way to avoid corrosion to the sides and delicate components of your hot tub.
- Allow the water to balance: Allow the pump to run for 4-6 hours. This will give the alkalinity decreaser and water ample time to mix properly.
- Retest alkalinity again. Carry out a test to determine the alkalinity and p If you did it correctly, the values should have been balanced. However, if either of them is not balanced, repeat the process above till the alkalinity is balanced.
Can I use baking soda to lower the alkalinity in my hot tub?
No, that would be a waste. Baking soda is an alkaline substance (it has a pH of 8.3). Though it might not be the most alkaline substance(there is soda ash), it will increase the alkalinity rather than reduce it. So don’t waste your baking soda on your hot tub if it is already alkaline. Leave it in the kitchen.
Will baking soda hurt my hot tub?
No, it won’t.
Baking soda is found in most of our kitchens, where it is majorly used as a leavening agent. So if you don’t know, it can serve a purpose in your hot tub. It can double both as a pH increaser and an alkalinity increaser.
Baking soda is a wonderful natural alternative to some other chemicals you might use to increase alkalinity in your tub. It isn’t toxic and doesn’t leave any harmful byproducts behind. As long as it is used in the right quantities and at the right time, baking soda won’t harm your tub.
What happens if alkalinity is high?
When the alkalinity in your tub is too high, it can lead to a number of issues. I will list them below:
- Cloudiness: One of the major indicators of high alkalinity is cloudiness. Your tub water becomes hazy. This could be as a result of the precipitation of calcium carbonate. At this point, your water’s LSI (Langelier Saturation Index) must have been exceeded.
A perfect LSI is 0.00, but an acceptable range is between -0.30 and +0.30. When the value exceeds +0.30, the water becomes scale-forming and that’s when calcium carbonate begins to precipitate into the water. In simple terms, the LSI refers to how saturated your water is with calcium carbonate. Hence, when the LSI is exceeded, there is cloudiness and haziness in your water.
- Scale buildup: As explained above, high alkalinity can cause your tub’s water to be scale-forming. Apart from being just cloudy, these scales can begin to deposit on your hot tub‘s surfaces. These scales are usually very hard and can cause other issues. You will also notice white flakes coming out of your water jets.
- Circulation problems: Due to these flakes circulating in your water, it can lead to water flow problems. These flakes can clog up pipes and your filter. This will reduce the rate at which water in your hot tub flows, thus affecting circulation.
- Damage to pumps: When your pumps are clogged with scale, they are being forced to run harder, in order to circulate more water. This can cause them to come under more intense pressure. As a result, cracks and striations could begin to appear in your pump. This can greatly shorten their lifespan and longevity.
- Sanitizers are rendered ineffective: When alkalinity levels are way above normal, your sanitizers (chlorine and bromine) are rendered ineffective. These chemicals work very well within a certain pH and alkalinity range. Outside that, they are practically useless. So ensure that your alkalinity levels are in order before introducing your sanitizers.
- Algae buildup: For the reason just mentioned above, where alkalinity affects sanitizer efficiency, this is the result. When sanitizers such as chlorine and bromine are no longer effective, organisms such as algae and bacteria will have a field day. There is nothing to inhibit their growth and buildup. This is what high alkalinity can lead to.
- Health issues: high alkalinity doesn’t just affect the hot tub alone, it can also affect you. High alkalinity goes hand-in-hand with high pH. These two can cause itchy skin and eyes. If you are someone who has skin or eye allergies, it is best to stay out of such water.
What causes high alkalinity in hot tubs?
High alkalinity can be linked to a number of causes. When you add too many chemicals to a pool, such as overestimating the amount of baking soda or soda ash in your pool. Also, the lotions and creams that bathers rub on their skin can contribute.
In addition, if you live in a hard water area and that also happens to be where you source your tub’s water from, then that could be the cause. Hard water is quite alkaline. This is due to the fact that it already has some calcium salts dissolved in it.
How much baking soda do I put in my spa if the alkalinity is low?
If your spa’s alkalinity is low, baking soda is a good option to increase the alkalinity. It is recommended that you put 1 tablespoon of baking soda in every 100 gallons of water. This means if your spa is 500 gallons, then you will need 5 tablespoons. Just make sure that you are testing it as you go on, to avoid overdosing your tub.
Can I use baking powder in my hot tub?
Yes, you can. As mentioned above, baking soda doesn’t just belong in the kitchen. It does a great job of increasing your alkalinity. It is also quite safe and not toxic.
Will alkalinity decrease on its own?
Yes, it can. However, high alkalinity levels might not just reduce in the time frame that you desire. In such cases, it is best you take the decision into your own hands and take steps to reduce it. It is not advisable to leave water with high alkalinity levels for extended periods in your tub. The side effects have already been discussed in detail above.