A swim spa allows you to enjoy fitness, relaxation, and family fun all in one place. But just like a pool or a hot tub, water care is key to making the most of your investment. With proper swim spa water care, you can keep it squeaky clean and functioning properly for years to come.
In this guide, we walk you through everything you need to know about swim spa water care, from chemistry basics to routine maintenance tips and more. Whether you already own a swim spa or you’re considering adding one to your home, this guide will help you keep your water balanced, clean, and crystal clear.
Swim Spa Water Chemistry Basics
Clean water is essential for keeping your swim spa safe and enjoyable. But crystal-clear water is about more than spa covers and hygiene habits alone. At its core, water care centers around chemistry. But don’t worry—there’s no need to dig out old flashcards from high school.
Below, we outline exactly what you need to know about swim spa water chemistry to keep it clean and perfectly balanced with ease:
Ideal pH Balance for Swim Spas: 7.4–7.8
The pH scale is one of the most important parts of swim spa water chemistry. The pH scale ranges from 0-14, measuring how acidic or alkaline (basic) your water is. For swim spas, the sweet spot is a pH of 7.4–7.8. Staying within this range keeps the water safe, clear, and comfortable, all while protecting your spa’s internal components.
To understand why this range matters, here’s how different pH levels affect your water:
- Acidic (pH below 7): Acidic water is corrosive, which can wear down and damage pumps, heaters, and fittings over time. It may also irritate the skin and eyes.
- Neutral (pH 7): Neither acidic nor Alkaline (basic). This level is generally safe for swimmers and gentle on spa components.
- Alkaline/Basic (pH above 7): High alkalinity can reduce sanitizer efficiency, encourage mineral buildup, and cause cloudy water. It may also cause skin and eye irritation.
Keeping your swim spa pH balanced within 7.4–7.8 ensures the water stays clean, comfortable, and equipment-friendly.
Ideal Calcium Hardness for Swim Spas: 180–250 ppm
Calcium hardness refers to the amount of dissolved calcium in your water. For swim spas, the ideal range is 180–250 ppm (parts per million). Maintaining this balance is essential because both high and low calcium levels can harm your water quality and your spa’s internal components.
Here’s how each imbalance affects your swim spa:
- High calcium hardness: Often called “hard water,” this means the water contains too much calcium. Excess calcium can lead to cloudy water and scale buildup, which damages internal components and reduces overall system efficiency.
- Low calcium hardness: When there isn’t enough calcium in the water, the water becomes corrosive. This can erode surfaces, equipment, and plumbing, cause staining, and even make the water feel slimy.
Maintaining proper calcium hardness keeps your swim spa protected, efficient, and comfortable to use.
Ideal Sanitizer Levels for Swim Spas
Sanitizers are essential for keeping swim spa water safe, clear, and free from bacteria and algae. Swim spas typically use one of the following water sanitation systems:
- Chlorine: A fast-acting sanitizer that destroys bacteria and organic contaminants. Dichlor, a granular stabilized chlorine, is recommended for swim spas because it dissolves quickly and is gentler on equipment.
- Ideal Chlorine Level for Swim Spas: 0.5–1 ppm (free chlorine)
- Bromine: A popular alternative to chlorine that’s gentle on skin and eyes, stable in sunlight, and generally remains active for longer after it’s applied.
- Ideal Bromine Level for Swim Spas: 1–3 ppm
- Ionizers: Mineral-based sanitizer systems that release copper, silver, or zinc ions into the water to inhibit bacteria and algae growth. Ionizers are usually paired with a small amount of chlorine or bromine, helping reduce chemical use and create softer-feeling water.
Regardless of which sanitizer you choose, maintaining consistent levels is key to keeping your swim spa clean, inviting, and safe to use.
Ideal TDS Levels for Swim Spas: < 1,500 ppm
As a general guideline, most swim spas operate best when the Total Dissolved Solids (TDS) levels remain within about 1,000–2,000 ppm, or no more than 1,500 ppm above your water’s original TDS at startup. That means if your tap water begins around 500 ppm, your “maximum safe zone” is roughly 2,000 ppm before water quality starts to decline.
Total Dissolved Solids (TDS) refers to the combined amount of minerals, salts, metals, and other dissolved materials in your swim spa water. As you use your spa, TDS naturally increases due to added chemicals, sweat, soaps, and environmental debris. While this rise is normal, letting TDS climb too high can make sanitizers less effective and leave your water looking dull or cloudy.
For most swim spas, TDS becomes a concern once levels exceed roughly 2,500 ppm. At this point, the water is harder to balance and may no longer respond well to regular chemical adjustments. If TDS levels surpass 2,500 ppm, you will need to partially drain and refill your swim spa to restore water clarity.
Keeping an eye on TDS and refreshing your water when needed helps maintain crystal-clear, comfortable, and easy-to-manage swim spa water.
Swim Spa Water Filtration
Water chemistry isn’t the only part of keeping your swim spa clean. You’ll also need a way to filter out debris. Even if you have an indoor swim spa, it’s still possible for contaminants to find their way into the water. That’s why swim spas have built-in filtration systems to capture debris like leaves, hair, or bugs before they do.
Many Endless Pools swim spas use internal skimmer filters to trap contaminants. They house cartridges made from pleated fabrics like polyester, which need to be cleaned and replaced on a regular basis to keep your swim spa water in good condition.
Cleaning a Swim Spa Filter Cartridge
Cleaning your filter cartridge about once a month extends its lifespan, helping your swim spa stay cleaner for longer. Soaking it in a filter cleaning solution removes buildup to keep the cartridge functioning properly. You can clean and reuse most swim spa filters up to 2–3 times.
Replacing a Swim Spa Filter Cartridge
While filters can last a long time with regular cleaning, cartridges need to be replaced about every 4 months. However, you may need to replace them sooner depending on how often you use your swim spa, water quality, and environmental conditions.
Water Care Products Every Swim Spa Owner Needs
You will need a few essential products to balance your swim spa water chemistry and keep filters functioning as they should. Below is a basic overview of swim spa supplies to stock up on:
Swim Spa Water Testing Supplies
Balanced water chemistry is all about consistent and accurate testing. You’ll need test strips or digital strips to monitor pH, calcium hardness, sanitizer levels, and TDS.
It’s recommended to stick to the following schedule to keep your swim spa clean and functional:
- Daily (or with every use): pH and chlorine
- Weekly: total alkalinity and total chlorine
- Biweekly: calcium hardness
It’s a good idea to keep a detailed record of testing results so you can track any patterns or changes over time.
Water Sanitizers
To keep your swim spa water crystal clear, you’ll need a regular supply of sanitizers like chlorine, bromine, or ionizers. These are available in the form of cartridges, tablets, or liquid solutions. Each product has its own unique instructions for how often to use it and how much to add to the water.
Balancers
In addition to sanitizers, you’ll also need balancers to ensure optimal water chemistry levels. These solutions are designed to either increase or decrease alkalinity, calcium hardness, and more. Along with regular testing, balancers are essential for maintaining sparkling clean water.
Shock Treatment
Oxidizing is the process of using chemicals to break down accumulated oils, lotions, and organic material that survive regular sanitizers. Shock treatment gives your swim spa a dose of oxidation to combat cloudy, foamy, or foul-smelling water. This not only keeps your spa clear but also extends the time spent between full drains, helping the water last longer.
Swim Spa Water Care Checklist
Maintaining a consistent water care routine prevents small issues from becoming costly repairs over time. Below is a standard swim spa water care schedule to keep your water and system clean, safe, and enjoyable:
Weekly Water Care
Complete these swim spa water care tasks at least once a week:
- Test, adjust, and track total alkalinity and total chlorine levels
- Add a shock treatment to refresh the water
- Rinse your filter cartridge with a gardening hose
- Inspect water clarity and foam levels
Biweekly Water Care
Every two weeks, complete these water care maintenance tasks to keep your swim spa clean and fresh:
- Test, adjust, and track calcium hardness levels using a scale defense solution
- Inspect water clarity and foam levels
- Inspect surfaces for scale buildup or residue
- Use a skimmer net to remove leaves, bugs, and larger debris
Monthly Water Care
Complete these swim spa water care tasks at least once a month:
- Deep-clean your filters by soaking the cartridges in an appropriate cleaning solution
- Inspect water clarity and foam levels
- Inspect surfaces for scale buildup or residue
- Partially drain and refill the water (make sure to balance the water chemistry after)
Seasonal or As-Needed Water Care
Complete these swim spa water care tasks each season or as needed:
- Replace filters every 4 months or as needed
- Fully drain, refill, and balance the water
- Review water testing notes and records to see what chemical adjustments are needed
- Schedule professional swim spa maintenance to have an expert clean and inspect your swim spa, which helps maintain water quality
Shop Swim Spas and Water Care Products at Creative Energy
Owning a swim spa is about enjoyment and relaxation, not stress. With a clear understanding of water chemistry, a few essential supplies, and a consistent water care schedule, you can keep your swim spa in peak condition for years to come.
Whether you’re looking to simplify your water care routine or bring home a swim spa of your own, now’s the perfect time to take the next step. Our expert team will happily guide you through choosing the best model, stocking the right water care products, and ensuring your spa setup is as stress-free as possible.
Contact us online today or visit any one of our Bay Area showrooms in Concord, San Rafael, San Mateo, or Dublin to experience the benefits of swim spas for yourself.