How to Balance Swim Spa Water: The Easy, Complete Guide

It’s the key factor in making your swim spa look great and last longer — not to mention, enjoy it!

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

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

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

The top 3 key components to keep swimming pool 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 – swim spa surfaces and equipment are protected from damage, and the sanitizer works effectively to keep the swim spa water clean, clear, and comfortable.

Simply stated, “balanced water” describes swim spa 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:

Swim spa professionals use the Langelier Saturation Index (LSI) calculator. It gets a bit complicated, but if you’re interested, you can find out if your swim spa 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 swim spa water.

Many factors affect your swim spa water balance, including frequent, heavy swim spa 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 swim spa’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 Swim Spa 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 swim spa surfaces and equipment. Plus, its harsh and irritating.

Swim spa water that’s too alkaline can cause scaling, which also damages swim spa surfaces and equipment, and is uncomfortable to soak in.

Balanced water is neither corrosive nor scaling. But here’s the thing: your swim spa 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 Swim Spa Water Balance?

TDS is the total of all dissolved solid matter in the swim spa 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 swim spa 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 swim spa 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 1,500 ppm will need to be addressed. The only way to remedy high TDS levels is to partially drain the swim spa 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.

Swim Spa Water too Acidic?

Swim spa 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. Swim spa water will begin to corrode and etch away swim spa walls, surfaces and anything metal, like heating elements to pump seals, heaters, underwater light fixtures and jets.

Swim Spa Water too Alkaline?

Once swim spa 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 swim spa 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 swim spa filters, in pipes, and pumps; it decreases water circulation, and damages swim spa components.

Balanced water protects surfaces and water quality.

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

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

Balanced water also allows your swim spa’s sanitizer to work more effectively.

Sanitizing Your Swim Spa

One of the biggest factors that influences a swim spa sanitizers ability to effectively clean the water is its pH level.

The ideal pH level should be between 7.2 – 7.6.

If swim spa 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 swim spa 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 swim spa 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.

The Secret to Clean, Clear Water: Keep it Balanced.

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

However, testing and adjusting it regularly shouldn’t take much time. Simply keeping your swim spa’s water balanced and the sanitizer level in check makes soaking in your swim spa much more enjoyable, and can help your swim spa last even longer. It can save you the hassle and expense of replacing broken swim spa equipment.

And best of all, soaking and swimming in your swim spa will be much more enjoyable – no more itchy skin or red eyes.