Can You Use a Hot Tub if the Alkalinity Is Low or High?

By Calvin | Last Updated: July 25, 2021 | Maintenance / Water Chemistry

The relaxation and comfort that a hot tub gives make you want to use the hot tub every time. But can you use a hot tub if the alkalinity is low or high? Here is the answer to that.

You shouldn’t use a hot tub if the level of alkalinity in the water is below 80 ppm or above 120 ppm (parts per million). Bathing in hot tub water with low or high alkalinity will cause health problems. Also, running your hot tub with water that has low or high alkalinity can damage the hot tub.

But that’s not all. There is more to know about hot tub alkalinity and this post digs right into the topic. So let’s get on with it.

Can you go in a hot tub if the alkalinity is high or low? No, you shouldn't do that.

Why Is My Hot Tub Alkalinity Always High?

Your hot tub alkalinity is always high because the total alkalinity of the water is off balance. When the total alkalinity of the water is off, there would always be sudden changes in the pH levels of your hot tub especially a high alkaline reading.

Why Is My Hot Tub Alkalinity Always High?

The total alkalinity of your hot tub is often referred to as the “buffer” of the water. The total alkalinity determines the ability of the water to resist sudden high changes in the pH level.

For the hot tub’s pH level to be within the recommended range (that is between 7.2 and 7.8 on the pH scale), the total alkalinity has to be in the right balance. If the total alkalinity is higher than 120 ppm, then the hot tub water will always have a high alkaline reading because the buffer that keeps the pH level in range is off balance.

Your hot tub water can also have a constant high alkaline reading if the source of water has high alkalinity. Most hot tub owners that fill their hot tubs with water from the well usually complain about a high alkaline reading.

This is because well water has a host of minerals and irons in it that it gets from the ground. So if you fill your hot tub with well water, it could be the reason for a consistent high alkaline reading.

There are several reasons for having a high alkaline reading in the hot tub. It could be because of a mixture of hot tub chemicals. When you mix different brands of hot tub chemicals, the resulting mixture can increase the pH level and alkalinity of the water.

Also, lack of sanitizers or shock in the water, inadequate cleaning routine, hot tub contaminants, and the likes can cause a high alkaline reading in the hot tub. But none of these is enough to cause the alkalinity to be constantly high. If the alkaline reading of your hot tub is always high, it’s because the total alkalinity is off.

Related Read: Can Too Much Chlorine or Bromine Hurt Your Hot Tub?

What Causes Alkalinity to Drop in a Hot Tub?

A drop in the alkalinity of a hot tub is usually caused by a high dose of hot tub chemicals. When you add a high dose of hot tub chemicals to the water, the pH and alkalinity of the water will be dropped. 

The alkalinity of your hot tub can be dropped by different factors ranging from natural events like acid rain to bathers’ filth including sweat and urine. Even subsequent changes in the temperature of the water can lower the alkalinity of the water by releasing carbon dioxide in the hot tub.

The usual culprit of a drop in hot tub alkalinity is a high dose of chemicals in the water, especially hot tub chlorine shock.

When you shock the water or add a high dose of chemicals to the water, the pH level and alkalinity of the water will be dropped. This is because hot tub chemicals like chlorine usually have an acidic level of 3 on the pH scale. Chlorine shock especially can raise the chlorine in the water to as high as 10 ppm. This high chlorine reading results in a low pH level and subsequently, a drop in the alkalinity of the water.

The alkalinity can also drop due to natural events like acid rain. If you usually leave your hot tub uncovered or you use the hot tub frequently in the rain, then you are exposing the water to rainwater. Excessive rainwater getting into the hot tub will dilute the water and can cause a drop in the alkalinity of the hot tub. Acid rain especially has a low pH reading. This can also cause a drop in the alkalinity of the hot tub.

Other possible causes of a drop in the alkaline reading of a hot tub include sweat and urine, yes urine from the bathers, food and drink residue, and body oils.

Related Read: How To Raise Alkalinity in a Hot Tub?

What Should My Alkalinity Levels Be in a Hot Tub?

The ideal total alkalinity for a hot tub is between 80 ppm and 120 ppm (parts per million). The alkalinity shouldn’t be higher than 7.8 on the pH scale. To test the alkalinity of the hot tub, you should use hot tub test strips.

What Should My Alkalinity Levels Be in a Hot Tub?

The alkalinity of the hot tub is a bit different from the total alkalinity. The alkalinity is measured using the pH scale. Alkalinity tells how acidic the water is on the pH scale.

Any reading above 7 is considered alkaline. Total alkalinity on the other hand measures the capacity of the water to neutralize acids or keep the pH level in range. Total alkalinity is measured in parts per million (ppm). Any reading between 80 ppm and 120 ppm is ideal for a hot tub.

So can too much alkalinity damage your hot tub? Let’s find out.

Related Read: How To Lower Alkalinity Levels in a Hot Tub?

Can Too Much Alkalinity Damage Your Hot Tub?

Too much alkalinity can damage your hot tub by causing hot tub scale. Hot tub scale is a whitish and flaky substance that forms on the components of the hot tub. Scale can cause malfunction and premature damages to several parts of the hot tub.

When you have too much alkalinity in the hot tub, the water will become scale forming. The scale mainly attacks the metal parts of the hot tub. This includes the heating mechanism, the jets, the shell, and the circulation pump. Hot tub scale will also affect other parts of the hot tub where water circulates through like the filtration system and the plumbing lines.

If left unattended, the scale will cover the heater making it difficult for water to reach the heating mechanism. Since water can’t reach the heating mechanism, the heater has nothing to heat. This can cause the heater to burn out.

Hot tub scale can also affect water circulation by clogging the plumbing lines. This will cause the pressure to mount on the circulation pump.

Asides from scale formation, too much alkalinity in the water can also cause the water to become cloudy. The whitish flakes that fall from the scale formation float in the water and cause the water to become unclear and cloudy.

Too much alkalinity will also render the sanitizers and chemicals useless in the water. Hot tub chemicals and sanitizers work best in low pH levels. If the alkalinity is high, the sanitizers wouldn’t work well and hot tub scum will grow in the water to cause green water.

Overall, you will have a lot of problems on your hands if the alkalinity is too much in your hot tub, so it’s best to pay attention to it by testing the alkalinity once every week.

Related Read: Can a High Level of pH Damage Your Hot Tub?

Can You Go in a Hot Tub With High or Low Alkalinity?

You shouldn’t go in a hot tub with a high or low alkalinity. Soaking in hot tub water with an alkaline reading below 80 ppm or above 120 ppm can cause health problems and damage your hot tub.

If you go into a hot tub that has alkalinity above 120 ppm, you are soaking in bacteria-infested water. This is because hot tub water with high alkalinity wouldn’t have active chemicals and sanitizers. This means bacteria and even algae will roam free in the water. So when you soak in such a hot tub, you will come out with a host of bacteria on your skin.

The water will also smell and become cloudy when there is high alkalinity in it. To put it in simpler terms, you will come off worse than when you got into the hot tub.

You shouldn’t soak in a hot tub that has low alkalinity either. If the alkalinity of the hot tub is below 80 ppm, it means that that water is too acidic for you to soak in. Bathing in water with low alkalinity will lead to dryness of the skin. Not to mention the stinging sensation you will feel in your eyes when you get out of the water.

Asides from the health problems that you will experience, the hot tub will also get damaged when you run it with water that has low or high alkalinity. If the water has a low alkaline reading below 80 ppm, the hot tub will suffer from corrosion, staining, and discoloration. If the alkalinity is high, the hot tub will suffer from scale formation, clogged pipes, and cloudy and algae-infested water.

So whatever you do, stay away from the hot tub when the alkalinity is off balance.

Does Raising Alkalinity Raise pH?

When you raise the alkalinity of the hot tub, you are also raising the pH level of the water. This is because a higher pH will also lead to a higher alkalinity level in the hot tub.

Though total alkalinity and pH levels are a bit different in meaning, they still work together. When you add a substance to the water to raise the alkalinity of the water, you are also indirectly raising the pH level of the water. Both the pH and alkalinity of the water can be affected by the same substance.

A raise in one level will correspond to a raise in the other level. This is the same when you lower the alkalinity. Lower alkalinity will also lower the pH levels of the water. However, the degree of the raise or drop might differ.

Related Read: Things That Can Affect Your pH Levels?

Final Words

Overall, high or low alkalinity in your hot tub is no reason to panic as long as you deal with the problem early on.

If you discover that the alkalinity in your hot tub is higher or lower than the recommended level, you should adjust the levels before using the hot tub. You should also test the water in the hot tub regularly to stay ahead of any sudden changes in pH levels or total alkalinity.

So there you have it. If you liked this post, ensure to check out others like it on this website for more hot tub tips. Have a nice day.

Hi, I'm Calvin Hall, the owner of Hot Tub Wiki. I worked at a local Spa Service for a few years before creating this website. I have owned several hot tubs and fixed a thousand of them. So, I know a thing or two about hot tubs.