How Much Muriatic Acid To Lower Alkalinity In A Hot Tub?

Muriatic acid is a solution that contains only 31% hydrochloric acid (HCl). It is not really as scary as it sounds. Neither is it dangerous, but should be handled with extreme care, especially during the process of applying it in the pool.

There are different applications for muriatic acid when it comes to the chemistry of pool water. They are;

  1. Lowering the pH of tub water
  2. Lowering the alkalinity of water: lowering your tub’s alkalinity requires more acid than when you want to lower the pH level. To lower the pH, you will probably use between 2 and 5 cups of hydrochloric acid. However, if the alkalinity of your tub is very high, you will need to use 1 or 2 gallons of muriatic acid.

Pour one gallon of the acid into a 5 gallon bucket, fill the bucket with 4 gallons of water, and dilute the acid in the bucket of water before pouring into the tub.

You need to dilute the acid because it is heavier than water. If you just pour it directly into the spa without diluting first, it might settle at the bottom and start eroding the tub.

Is high alkalinity bad in a hot tub?

You have just dipped your test strip into your hot tub water and noticed that the alkalinity is high. Is that a bad thing? Absolutely.

You should never get into a pool with high alkalinity or even leave it that way because, for starters, high alkalinity leads to high pH, and high pH does not only cause cloudy water but can cause scale buildup too.

More importantly, it can render your water sanitizer and shock totally ineffective, meaning bacteria can thrive and can potentially be lurking or floating around in the water, which is very dangerous to your health or anyone using the pool.

The alkalinity of your hot tub should be in the neutral range of 80 to 120 parts per million.

What should the total alkalinity be in a spa?

If the alkalinity of your pool is too low, it can lead to cracking and etching of your acrylic tub. If it is too high, it can lead to bacteria buildup in the pool and hot tub rash for anyone who enters.

Before you conclude that your hot tub alkalinity is low or high, it means you have checked it first to know how many parts you need to either increase or decrease it by.

The good and neutral level of the hot tub water should range between 80 and 120 parts per million.

What do you do if alkalinity is high in a pool?

You do not have to be a chemist to understand the water chemistry of your hot tub and how to lower or increase the alkalinity or pH of the water.

To reduce the alkalinity of your tub water, first you have to test the water to know how low it is and how many gallons of products you will need.

Then you can go to your local pool store and get a good Alkalinity Down or get a product that will work both on the alkalinity and pH at the same time, because an increase or decrease in the pool’s alkalinity indirectly affects the pH.

You can get muriatic acid, measure it according to your pool size, dilute it and apply it for this purpose too.

How do I bring my alkalinity down in my hot tub?

If the alkalinity level of your hot tub is too high, it can reduce the sanitizer efficiency of your tub and make the water turn green.

To be able to lower your water alkalinity level, you also need to check and neutralize your pH level.

Follow these steps to bring your alkalinity level down.

  • Always drain and clean your hot tub every 2 to 3 months.
  • Avoid using excessive amounts of chemicals in the hot tub.
  • Check your water source.
  • Use the right chemicals like the pH decreaser, which is also known as sodium bisulphate.
  • Determine how much water your tub can hold, test it, and understand the proper chemicals to use.
  • You can use the broadcast method to apply the chemicals, but if you notice the wind is blowing, you should try diluting first in water before pouring into the pool.
  • Allow water to circulate for at least 30 minutes before retesting or waiting for the next day to retest. If you still do not get the result you want, then you can try contacting help from a professional pool maintenance store.

How long does muriatic acid take to lower alkalinity?

After diluting the muriatic acid in a bucket of water according to whatever measurement you are following, pour it into the pool by circulating it round.

Make sure you do not pour the diluted acid on one spot because it might take more time. Make sure you brush the pool or use a rod to vigorously turn the pool to help the mixture.

Make sure your tub pump is on, then wait for 15 to 30 minutes before testing again. Before swimming in the hot tub, make sure you wait for a complete turnover cycle, which takes about 8 hours.

Should the pump be on when adding muriatic acid to the pool?

Whenever you add any chemical to the pool, make sure you put on the pump to help circulate the chemicals around to avoid them settling at the bottom of the pool and slowly making your pool liners and wall erode .

When you add muriatic acid, you should leave the pump on throughout for at least 8 hours to reduce the time you would have to wait for the water to manually circulate and to avoid the chemicals just sitting in one place.

How long after adding muriatic acid can I add chlorine?

When you try to mix two chemicals like muriatic acid and chlorine, it goes through an exothermic reaction and creates heat, which produces a very dangerous gas known as chlorine gas and hydrochloric gas that could be very explosive when exposed to UV light and can lead to skin burns.

In other words, it is not even good and safe to mix two chemicals together. If you do not want an explosion or major gas off, you should wait for at least 8 hours before adding chlorine to your pool after you have tested and confirmed that the alkalinity has been increased.

Can you put too much muriatic acid in a pool?

Before adding anything or chemicals to your pool, always test the water and make sure what you are about to use is in its right amount according to what your pool needs.

If you pour 14 ounces of the acid into a 10,000 gallon pool, it is going to affect both the alkalinity and pH by bringing it to a neutral level of 7.5 ppm from 8.0 ppm and the alkalinity to 4 ppm.

So you just have to figure out your size of pool and the number of gallons of water available before you know the right measurement for your pool. If you just pour the acid without knowing the amount to add, you might just add too much and change the water chemistry.

Will muriatic acid eat through PVC?

Muriatic acid can be very corrosive when touched with the bare hands or allowed to stay on any surface, making it burn. It will only affect your pool PVC when you add it excessively without using the right method.

Before applying muriatic acid to your water, it is advised that it should be diluted and the water should be turned or circulated to avoid the acid from settling and making the liners and walls erode.

How do you dilute muriatic acid?

Depending on the method that suits you, you can either pour the acid directly into the pool by using the circular method and using a long rod to stir the water vigorously. You can use a 5 gallon bucket. Fill it with 4 gallons of water, add one gallon of muriatic acid to the bucket of water, and also pour in a circular motion into the pool.

Although mixing in a bucket and pouring in the pool is preferable so that the acid is no longer corrosive before using it in the pool,

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