How to Balance Hot Tub Water: The Easy, Complete Guide

It’s the key to making your hot tub look great and last longer — not to mention, enjoying it!

Read on – we’ll tell you how to balance hot tub water so it’s easy to understand!

Hot tub water balance means keeping the water “just right” so it’s safe to swim in, feels comfortable, and doesn’t harm the hot tub surfaces or equipment.

However, out of balance water can make the hot tub water uncomfortable, and can also permanently damage the hot tub walls, deck, equipment and the other surfaces around your hot tub.

The top 3 key components to keep hot tub water balanced are:

• Total Alkalinity
• pH
• Total Hardness (also known as Calcium Hardness).

These components must be “balanced” or, kept within their proper levels called their “ideal range.” 

When these key components are balanced – within their proper levels – hot tub surfaces and equipment are protected from damage, and the sanitizer works effectively to keep the hot tub water clean, clear, and comfortable. 

Simply stated, “balanced water” describes hot tub water’s ideal condition; it has just the right level of  Total Alkalinity, pH, Total Hardness and Total Dissolved Solids (TDS) in relationship to the water temperature. 

The table below shows the optimal ranges for basic water chemistry:

Hot tub professionals use the Langelier Saturation Index (LSI) calculator. It gets a bit complicated, but if you’re interested, you can find out if your hot tub water is balanced by using the LSI calculator.

What Affects Water Balance?

Knowing what affects water balance is a key to understanding how to balance hot tub water.

Whether you own an in-ground or portable hot tub, the same factors affect your hot tub water balance. These factors include frequent, heavy hot tub use, organic matter that gets into the water like leaves or twigs, water you may add and even water temperature. Almost everything can alter the hot tub’s water chemistry.

However, these factors typically affect water balance the least!

The top 3 key factors that affect water balance are the levels and chemistry you’re constantly adjusting: Total Alkalinity, pH and Total Hardness.

That’s why it’s essential to test your water regularly, and adjust these levels as needed to maintain them within their ideal ranges.

Why it’s Important to Balance Your Hot Tub Water?

Essentially, balanced water means the water is not too acidic, not too alkaline, and all the mineral levels are balanced.

Water that’s too acidic can become corrosive, damaging hot tub surfaces and equipment. Plus, its harsh and irritating.

Hot tub water that’s too alkaline can cause scaling, which also damages hot tub surfaces and equipment, and is uncomfortable to soak in.

Balanced water is neither corrosive nor scaling. But here’s the thing: your hot tub water constantly changes. It seeks its own level by dissolving and “holding” minerals until it becomes saturated, and cannot hold any more – that describes TDS.

How Does TDS Affect Hot Tub Water Balance?

TDS is the total of all dissolved solid matter in the hot tub water. That includes minerals, metals, salts, contaminants like lotions or cosmetics and the chemicals used to keep the water sanitized. In general, anything you put in the hot tub water that dissolves adds to the TDS level.

You don’t need to check TDS levels as often as you check Total Alkalinity, pH and Total Hardness, but you will need to check them routinely – monthly is a good practice.

The issue is that TDS builds up as hot tub water evaporates, and the minerals, particles and chemical residues are left behind. High TDS can cause difficulty maintaining water balance, cloudy water, scale buildup, corrosion, and harsh water.

TDS levels above 1500 ppm will need to be addressed. The only way to remedy high TDS levels is to partially drain the hot tub and top it off with fresh water. Then, you’ll need to retest for TDS levels, and balance the Total Alkalinity, pH and Total Hardness levels.

Hot Tub Water too Acidic?

Hot tub water that doesn’t have enough minerals dissolved in it is typically more acidic and aggressive. It will attempt to saturate itself by dissolving everything it comes into contact with to build up its mineral content. The result: corrosion. Hot tub water will begin to corrode and etch away hot tub walls, surfaces, and anything metal, like heating elements to pump seals, heaters, underwater light fixtures and jets.

Hot Tub Water too Alkaline?

Once hot tub water becomes fully saturated, it will attempt to lose any excess minerals, particles or material in the form of scale, which it deposits on whatever the water comes into contact with. Scale looks like white or tan deposits, films or crystals.

Oversaturated hot tub water poses the greatest risk of scaling. It often looks cloudy and murky because of the excess particles floating freely in the water. If not corrected, scale can build up on hot tub filters, in pipes and pumps; it decreases water circulation, and damages hot tub components.

Balanced water protects surfaces and water quality.

Testing hot tub water and keeping the key components in balance will keep it from becoming too acidic or too alkaline.

Keeping your hot tub water balanced protects your hot tub surfaces and equipment from corrosion and scaling. Plus, water feels more comfortable and enjoyable to soak in.

Balanced water also allows your hot tub’s sanitizer to work more effectively.

Sanitizing Your Hot Tub

One of the biggest factors that influences a hot tub sanitizer’s ability to effectively clean the water is its pH level.

The ideal pH level should be between 7.2 – 7.6.

If hot tub water pH level is below 7.2, chlorine, as a sanitizer, dissipates much more quickly. That means you must add more chlorine. That costs more, plus, you spend more time adding chemicals to your hot tub water. And you may overchlorinate the water – resulting in itchy skin, red eyes, and faded swimsuits.

On the other hand, if the pH level is higher than 7.6, chlorine loses its ability to sanitize the water. This also means you must use more chlorine to achieve the same chlorine concentration as a hot tub with a balanced pH level.

Here’s an example:

If the pH is 7.2, you add one dose of chlorine.

However, at a pH of 8.2, chlorine concentration can only reach 15%, so you need to add more to achieve the same chlorine concentration.

At a pH of 8.2 you would need to add 5x the amount of chlorine you’d add at a pH of 7.2.

If you use bromine as a sanitizer, you’ll be happy to know that bromine isn’t as dependent on proper pH balance as chlorine is, but for all other reasons, you want to keep your hot tub water balanced.

The Secret to Clean, Clear Water: Keep Water Balance

Constantly checking and adjusting hot tub water balance may seem like a lot of work, especially if you don’t use the hot tub consistently.

However, testing and adjusting it regularly shouldn’t take much time. Simply keeping your hot tub’s water chemistry balanced and the sanitizer level in check can help your hot tub last even longer. It can also save you the hassle and expense of replacing broken hot tub equipment.

And best of all, soaking in your hot tub will be much more enjoyable – no more itchy skin or red eyes.