Salt systems are often praised as maintenance free, but is that really true? Our experts…
Why Do Salt Systems Work Well For Swimming Pools, But Not Hot Tubs?
We’re sharing why salt systems work well for swimming pools but not hot tubs.
While deciding on the kind of sanitization system they want for their hot tub, most people think back to their swimming pools. If a saltwater system worked well for my swimming pool, why should my hot tub be any different? Should I get a hot tub saltwater system? It contains water the same as a swimming pool doesn’t it?
However, while a saltwater system may have worked for your swimming pool in the past, it is not likely that it will work well for your hot tub.
We’re sharing why, even though a salt system may be suitable for your swimming pool, it might not be the best option for your hot tub.
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Salt in a hot tub at a glance
300–400gallons
typical hot tub water volume
104°Fsoak temp
burns off sanitizer fast
1,500–2,000ppm salt
stay in range or risk corrosion
Are Saltwater Systems Right for Your Hot Tub or Swim Spa?
Many owners considering a hot tub with saltwater system are drawn to the idea of softer water and reduced chemical handling, especially if they’ve enjoyed a saltwater swim spa or pool. Saltwater systems, which rely on a salt generator for hot tub sanitization, convert salt into chlorine to keep water clean. However, they’re not always the best fit for hot tubs. The smaller water volume, typically 300-400 gallons, combined with high temperatures around 104°F, creates challenges in maintaining consistent sanitizer levels. This can lead to saltwater hot tub problems, such as under-chlorination, which fails to combat bacteria, or over-chlorination, which risks damaging components. For those wondering, “Can you use pool salt in a hot tub?” the answer is no. Pool salt is formulated for larger volumes and higher concentrations, which can overwhelm a hot tub’s delicate balance and cause corrosion. Saltwater swim spas, with larger water volumes closer to spa pools, often handle salt systems better but still demand regular maintenance. Before committing to a hot tub saltwater system, consider whether the maintenance trade-offs outweigh the benefits compared to alternatives like chlorine or bromine, which offer simpler upkeep for most hot tub owners.
What Makes a Hot Tub Different From a Swimming Pool?
Size
The most notable difference is the size. An average hot tub is significantly smaller than the average pool. A hot tub carries approximately 300-400 gallons of water, while even the smallest swimming pools hold 3,000 gallons and can go upwards of 50,000.
Temperature
The water in a hot tub is much hotter than in the average swimming pool. While the temperature in a hot tub is adjustable, most users prefer to keep it around 104 F. How does this make a difference? Higher temperature means people in a hot tub will sweat more and excrete more organic material. Higher temperatures also causes chemicals to dissolve differently and burn off quicker.
Different Cover Types
Swimming pools are normally left uncovered during the swimming season. This allows the sanitizer in the pool to evaporate and vent off. Hot tubs, on the other hand, are usually covered between uses. Spa covers are also fully insulated compared to a more lightweight pool cover.
Internal Components
The components of a swimming pool and a hot tub have similar functions, but differences in design. Both units involve a pump or pumps, some sort of filtration system and possibly a heater, but the size and durability of these components varies. When you do not properly maintain your water or add the incorrect chemicals, these components are at risk of damage.
Material
Swimming pools are typically made of fiberglass, vinyl or concrete. Hot tubs have acrylic or smooth polymer shells. These shells are susceptible to damage with improper water maintenance.
How Do These Differences Impact Salt Systems in Hot Tubs?
To grasp how these differences negatively impact the salt system in a hot tub, consider a family of three in a 12,000-gallon pool as compared to three people in a 300-gallon hot tub. Since there is a smaller volume of water, there is a higher concentration of dissolved organic substances including sweat, skin oil, sunscreen, and other bacteria. These substances consume the sanitizer at a much faster rate. To remain effective, the hot tub saltwater system would have to keep generating and maintaining a greater sanitizer concentration. However, this does not happen.
The high-temperature environment of the hot tub will make it difficult for the salt cell to produce enough sanitizer. Salt system manufacturers recommend adding extra sanitizer to keep the water safe and healthy.
Let’s also take into consideration the opposite scenario. What if the salt generator continues to run when there are not enough dissolved organics in the water to use the sanitizer? In this case, the generator will end up overproducing chlorine. This excessive chlorine can lead to the bleaching of the hot tub cover, shell, and pillows. If excessive chlorine is allowed to build up, it can even cause damage to the internal hot tub components.
Pro Insight • Epic Hot Tubs Service Team
“The salt routine that coasts along on a 12,000-gallon pool behaves nothing like it does on a 300-gallon tub. Fewer gallons and a 104-degree soak mean the sanitizer level swings up and down between sessions, so owners who expected set-it-and-forget-it end up testing and adjusting more often, not less.”
Why Saltwater Systems Work Better in Pools and Swim Spas
Saltwater systems, often praised in salt system pool reviews, thrive in swimming pools due to their large water volumes, typically 10,000 to 50,000 gallons, which dilute organic contaminants like sweat and sunscreen, making it easier for the salt generator to maintain consistent chlorine levels. Spa pools salt systems, as seen in larger swim spas, also benefit from this principle. A salt water swim spa, with water volumes ranging from 1,000 to 2,000 gallons, handles salt systems better than hot tubs because it more closely resembles a pool’s capacity and operates at lower temperatures, often around 80-90°F. These conditions reduce the strain on the salt cell and minimize the risk of over-chlorination. Saltwater spa pools, including dual-zone swim spas with separate hot tub sections, can effectively use salt systems for the swim area, though the hot tub portion still faces the same challenges as standalone hot tubs. While a salt system pool or saltwater swim spa offers a low-maintenance appeal, hot tubs struggle with the rapid sanitizer consumption caused by high temperatures and concentrated organics, making traditional sanitizers like chlorine or bromine often more practical for smaller spa setups.
Salt Systems Require More Maintenance in Hot Tubs
While salt systems may have been a financially viable option for your swimming pool, the same cannot be said for hot tubs. While many people in the industry claim that saltwater systems do not require much upkeep, are salt systems really maintenance-free?
The short answer: no.
Excessive chlorine in your hot tub can lead to the corrosion and damage of outer and internal hot tub components, making you spend money on repairs and replacements.
The salt cell cartridge also requires replacements every few months. These cartridges come in a pack of 3 and cost around $300. While maintenance can become easy once you get used to it, the cost of ownership remains a big factor.
Saltwater is also known to be harder, causing excessive wear and tear on equipment. This leads to the need to add water softening products which are an added monthly expense.
Addressing Salt Water Hot Tub Corrosion Concerns
Salt water hot tub corrosion is a significant concern for owners considering a hot tub saltwater system. The high salt concentration, combined with elevated temperatures, can accelerate wear on acrylic shells, metal fittings, and internal components like pumps and heaters. Unlike pools, where water volume dilutes salt’s impact, hot tubs concentrate these effects, leading to pitting or rusting over time. Saltwater hot tub problems, such as corrosion, can also affect aesthetic elements like jets and pillows, resulting in costly repairs. To mitigate corrosion, regular water testing is crucial to ensure salt levels remain within manufacturer-recommended ranges (typically 1,500-2,000 ppm). Using corrosion-resistant components, if available, and flushing the system periodically can help. However, even with these precautions, the risk of corrosion makes saltwater systems less practical for hot tubs compared to chlorine or bromine, which pose fewer long-term risks to your spa’s durability.
Pro Insight • Epic Hot Tubs Service Team
“On service calls the tell-tale signs of a salt system running too hot are bleached pillows and a faded cover, then pitting on the metal jets and fittings. On a small, hot, tightly covered tub it shows up years sooner than it would on an open pool. Keeping salt in the recommended range and testing regularly is what buys that hardware more time.”
Choosing the Best Hot Tub Sanitization System
Selecting the best hot tub salt system or alternative sanitization method depends on your maintenance preferences, budget, and spa usage. While saltwater systems offer a luxurious feel, their challenges in hot tubs often lead owners to explore other options. Below is a comparison of common sanitization systems to help you decide.
| Sanitization System | Pros | Cons | Approx. Monthly Cost |
|---|---|---|---|
| Saltwater | Softer water, less manual chemical handling | High maintenance, corrosion risk, expensive salt cell replacements | $20-$40 |
| Chlorine | Cost-effective, widely available, reliable | Strong odor, skin irritation for some | $10-$20 |
| Bromine | Gentler on skin, stable at high temperatures | Slightly higher cost, slower to dissolve | $15-$25 |
| Ozone | Reduces chemical use, low maintenance | High upfront cost, not a standalone sanitizer | $5-$15 |
For most hot tub owners, chlorine or bromine systems strike a balance between cost, ease of use, and component safety. If you’re set on a hot tub with saltwater system, ensure you’re prepared for regular salt cell cleaning and potential corrosion management to keep your spa in top shape.
The Bottom Line
While saltwater systems may have worked for your swimming pool, they may not be a viable option for your hot tub. With a hot tub saltwater system, you risk under and over-chlorinating your water, damaging the hot tub components and shell, and a much higher maintenance cost.
Consider the differences between a swimming pool and a hot tub carefully before choosing a sanitization system. If you are properly informed, you will save yourself much hassle and ongoing maintenance costs in the future.
Frequently Asked Questions About Saltwater Systems
Can you use pool salt in a hot tub?
No, pool salt is not suitable for hot tubs. It’s designed for larger water volumes and can disrupt the delicate chemical balance, potentially causing corrosion or equipment damage.
What is a hot tub salt water generator?
A hot tub salt water generator, or salt cell, converts dissolved salt into chlorine to sanitize the water. It requires regular cleaning and replacement to function effectively.
Are saltwater hot tubs maintenance-free?
No, saltwater hot tubs require regular salt level monitoring, cell cleaning, and potential water softening, making them more maintenance-intensive than chlorine or bromine systems.
Can a saltwater system work in a swim spa?
Yes, a salt water swim spa can use a saltwater system more effectively than a hot tub due to larger water volumes and lower temperatures, but maintenance is still required.
Is pool salt the same as spa salt?
Not exactly. Both are sodium chloride, but pool salt is formulated for the much larger water volumes and higher concentrations a pool holds. In a 300 to 400 gallon hot tub that same salt can overwhelm the smaller water balance and contribute to corrosion, so use the salt your spa or salt system manufacturer specifies.
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About The Author:
Richard Horvath
Hot Tub & Spa Expert
Richard has been in the hot tub & spa industry for years. As a long hot tub & swim spa owner himself, Richard has a passion for helping homeowners create their dream backyard.
