When it comes to hot tub alkalinity and pH, baking soda is one of the most popular alkalinity/pH adjusters among spa owners. If you are new to hot tub chemicals and pH balance, you may be wondering whether you can use baking soda to lower pH in a hot tub.
Baking soda is an alkaline substance, so it cannot be used to lower the pH of your hot tub(s). As an alkaline substance, it can only be used to raise the pH or alkalinity of a hot tub.
Nevertheless, there are other chemicals you can use to lower the pH in your spa. So, the best question to ask now is; how do I lower the pH in my hot tub? Or what chemical can I use to lower the pH in my hot tub?
How do I lower the pH in my hot tub?
To lower the pH level in your hot tub, you need to add an acidic substance or pH adjuster to the hot tub. The most popular chemicals which we would recommend are liquid muriatic acid and dry sodium bisulfate.
Either of these two chemicals can do the work perfectly well. However, if you are not comfortable with them, you can opt for pH reducer chemicals. You can find them in the pool stores around. They are also good for adjusting pH and/or alkalinity levels.
If you are suspecting that your spa pH is high, you need to validate your suspicion before you can add any chemical to it. To achieve that, you need to test for the pH levels with test strips or kits.
Get your test strip and follow the instructions on the pack. You simply need to dip the test strip in the hot tub water for a few seconds. Bring it out and match it against the color chart on the pack.
The generally accepted pH range is between 7.2 and 7.8. But always target 7.4-7.6. That’s the ideal range. For the alkalinity, you need a range of 80ppm-120ppm.
If the pH level is high you can then go ahead and add acidic compounds to the spa. But before you start, take note of the following;
- Do not add water to acid. You can only add acid to water to avoid splashing and damage.
- Ensure that no one is inside the spa when you are adjusting the chemicals.
Usually, alkalinity and pH are dependent on each other. The alkalinity level will be affected by pH adjustment. So, it’s better to work on the two during the adjustment.
Take note that pH level changes faster than alkalinity. The best practice is to target the alkalinity because the pH will eventually adjust to it. So, test for the alkalinity levels to know the right amount of acid to add.
The general rule is to add 1.3qt of muriatic acid to every 10,000 gallons of water or 1.6lbs of sodium bisulfate to every 10,000 gallons. This quantity lowers the alkalinity by 10ppm. However, ensure that you follow the instructions on the package.
Another thing to be mindful of is how you add acid to the hot tub to avoid damages to the floor and components of the spa. Instead of dumping the chemical, you need to add the it gradually.
Then turn the hot tub on to help circulate the chemical. After adding the chemical, allow the spa for about 3-6 hours. Test the levels again. If still low, repeat the process until you get to the required range.
How do I lower the pH in my hot tub without chemicals?
If you are not able to get hold of the chemicals mentioned above, or you don’t wish to use them, you can opt for natural compounds like vinegar.
We don’t recommend the use of vinegar as a pH reducer because it’s not the industry standard. You can use it as your spa cleaning agent. But a lot of spa owners have used it as pH reducer and said it’s nice.
However, some have complained that it makes the spa components deteriorate faster. So, using vinegar is one of the natural ways to lower the pH levels without chemicals.
A friend that uses it usually adds 4 cups intermittently until he gets the desired pH level. Once you add four cups, allow it for about 3-4 hours to mix thoroughly before you can test the level with your test strips. Meanwhile, ensure that the jets and filters are running to help circulation.
If the level is still high, add another four cups, wait, and test. Repeat the process until you get it right.
So, can I use vinegar to lower the pH in my hot tub?
Vinegar is a natural way to lower pH in your hot tub without chemicals. It works just fine and many hot tub owners use it often.
However, it is not the industry standard and we don’t recommend its use as a pH adjuster.
Dry sodium bisulfate and liquid muriatic acid remain the best pH reducers. They are industry standard and we recommend them for use.
But this doesn’t mean you cannot use vinegar at all. You can use vinegar when you are not able to get other chemicals. Don’t use it all the time as some spa owners have reported its damage on the spa components.
What causes high pH in a hot tub?
The pH level of your hot tub water can increase due to dissolved substances such as perfumes, body lotions, and makeup.
If you can notice, your hot tub pH usually goes down faster when you have many people using it. This is not a coincidence. It is so because you have more Total Dissolved Solids (TDS) when a lot of people use it at the same time.
The introduction of more alkaline compounds to the spa makes the pH rise faster.
Another factor that affects the hot tub pH is the nature of the water you use. Check the alkalinity reading of the water you use in your spa. The water from local suppliers in some areas has a high alkalinity level which also affects the pH of the hot tub.
Also, your swimsuit may be a culprit here. Do you wash your swimsuit with detergent or soap? If you do, then it could be a result of the detergent. You need to have a special swimsuit for your spa which you don’t wash with soap or whatever.
All you need to do to your swimsuit after use is to rinse with clean water and dry. You don’t need to wash it with soap.
Is high pH in a hot tub dangerous?
High pH in your hot tub is not safe for your health and it can cause burning eyes and itchy skin. It may not have an immediate health impact, but consistent use of it can affect your health negatively.
Moreover, it causes scale buildup in the hot tub and can cause damage to the pump, pipes, filter, etc.
So, it’s good to always test for pH if you are a regular user.
What should the pH be in a hot tub?
The pH level in your spa is very vital for your health and the lifespan of the equipment. The generally accepted range is 7.2-7.8.
Any level below 7.2 is too low. If it gets above 7.8, it’s too high and can cause permanent damage to your hot tub components.
What should be adjusted first, alkalinity or pH?
PH and total alkalinity are dependent on each other. Any change in alkalinity level usually affects the pH and vice versa.
Like we pointed out earlier, it is better to adjust the alkalinity level first before pH because it is easier that way. Moreover, pH can naturally adjust to any alkalinity level.
Again, it is very difficult to adjust the pH level when the alkalinity is off. So, always go for alkalinity first before the pH.
The alkalinity level should be between 80ppm and 120 ppm while the pH range is 7.2-7.8.
Does baking soda lower alkalinity?
Alkaline substances are not used to lower alkalinity. Baking soda is alkaline and can only increase alkalinity instead of reducing it.
There are special chemicals for reducing alkalinity such as soda ash (sodium bisulfate) and alkalinity increasers. You can get these chemicals in the pool stores.
Moreover, alkalinity can reduce by itself, if you can be patient enough to wait. You can only use baking soda when you want to increase alkalinity in your hot tub.
Is alkalinity increaser the same as baking soda?
Alkalinity increasers are not baking soda but they contain a high percentage of baking soda in them. You can consider baking soda to be an alkalinity increaser.
But alkalinity increasers are alkalinity adjustment chemicals produced mostly with baking soda.
