Can You Use a Hot Tub if the pH Is High?

By Calvin | Last Updated: June 23, 2021 | Maintenance / Water Chemistry

There are a few instances when you shouldn’t soak in your hot tub water. One of such instances is if the pH level of the water is high.

No, you shouldn’t use a hot tub if the pH level is high or above 7.8 on the pH scale. This is because the water in the hot tub at that time has a very alkaline reading and soaking in water like that can cause different problems to you. 

Not to mention the fact that running your hot tub with very alkaline water can also damage the hot tub by causing scale build-up and foam in the hot tub.

But this is just a quick snapshot. There is more to know about hot tub pH, the right pH level to soak in, and what to do if the pH level is too high. So let’s get on with it.

Your pH levels are very high, can you still use the hot tub? No, you can't. It isn't recommended to use the hot tub if the pH levels are above 7.8

Why Is the pH Level of My Hot Tub Always High?

The pH level of your hot tub is always high because the total alkalinity is off. The total alkalinity of the hot tub acts as a watchdog to keep the hot tub pH in the correct range. If the total alkalinity is off or too high, then you will likely have a consistent high pH level in the water.

The pH level in your hot tub could also be high because you added too much pH increaser or too much of a base or alkaline substance like baking soda to the water. If you accidentally spilled baking soda into your hot tub water, it can cause the pH level to be way above the recommended range.

The high pH level could also be a result of your source of water. Hot tub owners that fill their hot tubs with well water have often complained about having a very alkaline reading in the hot tub when they test the water.

Your hot tub water could also have a very high pH level if there isn’t enough sanitizer in the water. The sanitizers that you add to your hot tub water either chlorine or bromine have an acidic content. While the acidic content of each sanitizer varies, having less of the said sanitizer in your water can cause you to have a high alkaline reading in the hot tub.

On the other hand, having too many chemicals or sanitizers in the water can also cause a high alkaline reading. Having too many chemicals in your water will increase the level of TDS (Total dissolved solids) in the water and this can also increase the pH levels of the water.

Other causes of high pH levels in a hot tub include contaminants that fall into the water, hot tub oils, body care products, food residue, and the likes. Any of these can cause the pH level of your hot tub to get very high but if you notice that the pH level of the hot tub stays high consistently, then that is because the total alkalinity has gone wonky.

So what do you do if the water pH is too high? Let’s find out.

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

What Do You Do if the Spa pH Is Too High?

If your pH level is too high, the best thing to do is to reduce the pH level by adding a pH decreaser or pH minus to the water. A very common pH decreaser that you can add to your spa to lower the pH level is sodium bisulfate. Sodium bisulfate is a dry acid that dissolves in the water and it reduces the pH level over time.

If your pH levels are too high, then you should use pH decreased to lower the levels.

But lowering the pH level of your hot tub with a pH decreaser isn’t a one-time task. It’s more of a routine that you will need to carry out daily or weekly depending on the instructions on the container of the pH decreaser that you purchased.

If you add the pH decreaser all at once to the hot tub water, the water will become too acidic and you will need to add a base solution to up the pH again.

If you add too little, then you wouldn’t notice any changes in the pH level of the water. The right amount needs to be added regularly till you notice that the pH level has been lowered to the right level.

Related Read >>> Why is My Chlorine Level Always High?

What if the pH Decreaser Doesn’t Work?

If you added the pH decreaser or pH minus to the water and you can’t notice any changes in the pH level of the water, then chances are the pH level is actually higher than the test strips showed. Since the pH decreaser didn’t work, you can go a step further by adding liquid acid or liquid chlorine to the water. Another alternative is to shock the water in the hot tub. Any of these methods will lower the pH level of the water.

If for any reason, shocking the water or adding liquid chlorine still doesn’t lower the pH level of the water, then you need to drain the hot tub and refill it with fresh water.

Though this is very unlikely because hot tub shock and liquid chlorine have an acidic level of about 3 on the pH scale. That is more than enough to drop the pH levels of the water in the hot tub. But let’s say it doesn’t work, you know what to do.

Now, let’s dial down on all the high pH talk. What’s so bad about having a high pH level in your hot tub water? What can a high pH level cause in a hot tub? Keep reading to find out.

Related Read >>> How To Lower Chlorine or Bromine Levels?

What Should the pH Level in My Hot Tub Water Be?

The pH level of your hot tub water should be between 7.2 and 7.8 on the pH scale with 7.5 being the sweet spot. This is because water pH within this range is both safe for your hot tub and good for you to soak in. Any pH reading below or above this range is not ideal for hot tub water to have.

Your pH levels should be between 7.2-7.8. With 7.5 being the perfect number.

If the pH level is below 7 on the pH scale, then the water becomes slightly acidic for a hot tub. If it is above 7.8 on the pH scale, then the water pH is too alkaline for a hot tub.

The lower the pH reading, the more acidic the water gets and the last thing you want in your hot tub is water with a low pH. If the water in your hot tub has a low pH, then you can start to notice discoloration and staining on the shell.

Not to mention the fact that the acidic water can start to eat away or corrode the metal parts of your hot tub like the heater, the jets, and the shell. If these parts get corroded, it can cost a lot to repair or replace them.

You shouldn’t have a high pH reading in your hot tub either. While a low pH level will cause corrosion, a high pH level in the water will cause a nasty case of scale build-up, foamy water, and staining on the hot tub shell. This is why it’s very important to keep the pH level of the water in the hot tub at the right level (between 7.2 and 7.8).

Related Read >>> 6 Things That Could Be Affecting Your pH Levels

What Can High pH in a Hot Tub Cause?

Having a high pH level in your hot tub is not ideal for the performance of the hot tub. A high pH level in the hot tub can damage the hot tub and ruin your spa experience. Let’s take a look at some of the problems a high pH level can cause in your hot tub.

Scale Build-up

Having a high pH level or a pH level higher than 7.8 in your hot tub water can cause a nasty case of scale build-up in the hot tub.

Scale refers to a chalky substance that forms on the surface and body of the hot tub. The scale is primarily formed because of high pH level coupled with consistent high temperature, and low calcium levels in the water.

The hot tub scale is usually noticed on the hot tub shell, circulation pump, and heater. The scale usually has a whitish appearance and it can have a sandy feeling.

The hot tub scale can also affect the jets in the hot tub. If you notice white flaky substances floating in the water or coming out of the jets, then your hot tub has been affected by the hot tub scale.

Hot tub scale can cause dirty spa water, ineffective heating mechanism, and rust of the metal parts of your hot tub.

Low Sanitizer Effectiveness

If the pH level in your hot tub is too high, it can cause low sanitizer effectiveness. This means the sanitizers and chemicals you add to your hot tub to purify the water wouldn’t work as effectively as they should.

This is because hot tub sanitizers like chlorine work best in low pH levels or slightly acidic water. Since the hot tub water has a very alkaline or very high pH reading, the sanitizers wouldn’t be as effective as they should be.

This can quickly escalate to a bigger problem because if you don’t have active sanitizers in your hot tub, then the hot tub is prone to algae bloom, bacteria attack, hot tub scum build-up, clogging of the filters, and biofilm in the plumbing lines. Eventually, you will have green water in the hot tub.

Cloudy Spa Water

High ph levels in your hot tub water can also cause cloudy or unclear spa water. Cloudy water is caused by unbalanced water chemistry.

If you notice fluffy particles in the water or if the water seems unclear because of dry flakes floating on the surface, then you have cloudy spa water. The nasty thing about having cloudy spa water is that it can start to produce offensive odors.

Discoloration and Staining

Having a high pH level in the hot tub water can also cause discoloration and staining on the shell of the hot tub. Stains that are usually caused by high pH levels are usually green or brown. When the pH level is too high, the sanitizer wouldn’t work effectively and this can cause green water because there are too many contaminants in the water.

The green water can cause a greenish tint to appear on the shell of the hot tub. You can also notice a brownish tint forming along the waterline. This is a result of too much alkalinity in the water.

Related Read >>> How To Remove Hot Tub Stains?

Final Words

Overall, having a high pH level in your hot tub water is totally avoidable if you keep tabs on your water chemistry and pH levels by testing them regularly. If you ever notice that the pH level is off the recommended range, then you should fix it immediately by adding either a pH increaser or a pH decreaser.

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.