Salt water hot tubs generally offer a gentler soaking experience compared to traditional chemical-treated tubs. These systems use sodium chloride, or common salt, with a generator to produce a consistent, low level of sanitizer. This method bypasses the need for manually adding large, fluctuating doses of chemical sanitizers, which are often the primary cause of skin irritation. The result is water that feels softer and less harsh, helping maintain the skin’s natural balance.
Understanding Salt Water Hot Tubs vs. Traditional Systems
Salt water systems are not chlorine-free, but they utilize a salt chlorine generator instead of adding chlorine or bromine directly. This device passes the water, containing dissolved sodium chloride, over an electrolytic cell. Electrolysis splits the salt molecules, converting the sodium chloride into hypochlorous acid, the active form of chlorine sanitizer.
This mechanism provides a distinct advantage over traditional systems requiring manual addition of sanitizer. The salt system generates chlorine continuously and on-demand, maintaining a steady, low-level residual in the water. This consistent, lower concentration is less aggressive to the skin and eyes than the periodic high and low spikes that occur when chemicals are added manually.
The Skin’s Reaction to Saline Environments
The perceived softness of the water in a salt tub relates directly to its salinity, or Total Dissolved Solids (TDS). Salt hot tubs typically operate within a range of 1,750 to 3,000 parts per million (ppm) of salt. This concentration is extremely low, equating to about one-tenth the salinity of seawater, which averages around 35,000 ppm.
The human body’s internal salinity is roughly 4,500 ppm, meaning the hot tub water is significantly less salty than our own tissues. This low level of salinity minimizes the osmotic pressure that draws moisture out of the skin, which causes the dryness and “pruning” associated with soaking in highly saline water. The mild mineral content contributes to a smoother skin feel, similar to a mineral bath, without the dehydrating effects of high salt concentrations.
Sanitizer Impact: Low-Level Chlorine and Skin Comfort
The primary source of skin discomfort in traditional hot tubs is often the byproducts called chloramines. These compounds form when free chlorine reacts with organic matter, such as sweat, oils, and lotions, and they are responsible for the strong chemical odor, eye irritation, and skin dryness. The automated, low-level generation of sanitizer in salt systems significantly reduces the formation and buildup of these chloramines.
The continuous oxidation of the water means there is less opportunity for these irritants to accumulate, leading to a gentler experience for sensitive skin. Salt systems tend to promote more stable water chemistry, particularly the pH balance. Maintaining a pH level between 7.2 and 7.8 is important because acidic water can degrade the skin’s protective acid mantle, leading to irritation and a compromised barrier function. The balanced water chemistry helps protect the skin from the inflammatory effects of overly acidic water.
Maximizing Skin Health While Soaking
Even with the gentler nature of salt water, certain steps can optimize skin health during and after a soak. Before entering the hot tub, a quick rinse removes residual body products and oils, which limits the organic material that reacts with the sanitizer. This helps maintain the water quality and reduces the formation of chloramines, benefiting the skin of all users.
After soaking, follow these steps to protect your skin:
- Rinse the skin immediately with lukewarm water to wash away any residual sanitizer and minerals.
- Pat the skin gently to dry rather than rubbing, which helps preserve the skin’s natural oils.
- Apply a moisturizing product immediately after drying, ideally within a few minutes, to lock in hydration.
- Look for moisturizers containing ingredients like hyaluronic acid or ceramides, which help repair and reinforce the skin’s moisture barrier.
- Limit soak time to 15 to 20 minutes and avoid excessively high water temperatures to prevent the stripping of natural oils, a common cause of post-soak dryness.