Balancing Your Hot Tub pH Level & Total Alkalinity

Whether you own a hot tub or are looking into investing in one, it’s important to learn about balancing your water’s chemical levels to ensure that it’s clean, healthy and safe for bathers to use.

This guide helps you discover why balancing total alkalinity and pH is essential to keeping your hot tub or swim spa in top condition and your sanitisers working at their most effective.

Total Alkalinity is closely related to pH, and managing it is a key factor in maintaining healthy pH levels. When adjusting alkalinity, you’re also adjusting the pH levels and vice versa. We recommend getting your Total Alkalinity balance correct first as it acts as a buffer and prevents rapid pH fluctuations; plus, high pH levels are much more challenging to adjust.

So, let’s commence.

What is total alkalinity?

Hot tub TA Plus

Total Alkalinity is the measurement of dissolved alkaline substances in water. It helps control the pH level and acts as a barrier, so it must be balanced correctly.

A Total Alkalinity level between 80-120mg/l ppm must be maintained in your hot tub. Anything above or below this range makes balancing pH levels quite tricky to maintain.

Below 80mg/l ppm can cause your water to become corrosive and acidic and even stain or damage your hot tub surfaces. Algae may bloom if alkalinity drops which can cause you discomfort.

Above 120mg/l ppm can cause your water to become cloudy and allow scale to grow on pool surfaces and equipment.

What causes high alkalinity in a hot tub?

Adding too many chemicals, bacteria, or bodily oils such as sweat or lotions can cause high alkalinity. As can hard water, if you live in a hard water area.

What causes low alkalinity in a hot tub?

Rainwater can decrease your alkalinity levels and result in an acidic pH, so we always recommend using a hot tub cover. Using chlorine tablets that have a low pH level can affect it too.

What are pH levels?

Hot tub pH Plus

PH levels measure acidity and alkalinity in water on a pH scale. A pH scale is numbered from 0-14; a measurement of 7 is considered neutral or balanced.

A Ph level between 7.2 and 7.8 should be maintained in your hot tub.

7.2 or below indicates that your water is too acidic, which can cause itchiness and eye burn, and your sanitiser to be less effective. High acidity can result in costly damage to your hot tub parts too.

7.8 or above, like high alkalinity, can contribute to scale build-up, foam and cloudy water.

Keeping your pH levels in check creates a more comfortable environment for your bathers, avoids scale and calcium build-up, and will keep your tub free from corrosion.

Shop our full range of hot tub balancers.

How do you test total alkalinity and pH levels in your tub?

Hot tub water testing

We suggest using dip test strips to test the pH level, total alkalinity and sanitiser levels. They’re easy to use and provide quick and accurate readings, so you can make the proper chemical adjustments if required, all in the space of a few minutes!

Top tip: We recommend testing your spa water at least once a week, depending how frequently you use your hot tub, to keep it fresh and clean.

How do you increase low alkalinity and pH levels?

If you have a balanced pH level but low alkalinity, we recommend adding an alkalinity increaser, which in normal circumstances won’t affect pH levels.

If you have a low pH level, a pH increaser will help to reinstate the right pH. It’s important to check the alkalinity levels as pH increaser also raises this. Retest with test strips to check both are balanced.

How do you reduce high alkalinity and pH levels?

If you have high pH levels, a pH decreaser helps bring the level back within the normal range. It’ll bring the total alkalinity levels down too, so remember to test the water to check both levels.

For more information on how to take care of your hot tub, take a look at our chemical guide.

Parting advice

Need more advice? Give us a call on 01482 212322 or email and we’ll help you out. Or drop in and see us in our Hull or Leeds showrooms to see our hot tub chemical range for yourself. 

Not near one of our Yorkshire hot tub showrooms? No problem, if you’re looking for a new hot tub you can explore our virtual showroom or book a video call with our showroom team

Stay up to date with our latest products, hot tub guides and updates on Facebook or Instagram.

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