Salt water pools came to being in 1972 when New Zealand company Cascade pioneered the idea of electrifying salt and converting it to chlorine for the purpose of sanitizing swimming pools. In the 1980s salt water pools began to gain in popularity in North America and today are widely available globally with salt water chlorination systems produced by many well-known manufacturers.
A salt water pool only requires a low amount of salt at any given time to operate properly. Salt chlorinator manufacturers typically recommend a range of 2,700 – 3,400 parts per million (ppm) salt content in the pool. By comparison a human tear has about 9,000 ppm salt content and the ocean water is about 35,000 ppm. So a salt water pool’s salt content is much lower.
In that regard, salt water pools won’t cause eye or skin irritation for most people the way chlorinated pools often do.
Can You Open Your Eyes In A Salt Water Pool?
You can open your eyes under water in a salt water pool without fear of eye reddening and irritation as is often the case in the ocean or in a regularly chlorinated pool. The salt level in the ocean is around 35,000 parts per million (ppm) whereas the salt content in a salt water pool is around 3,000 ppm when in the correct range.
One of the benefits of a salt water pool is that the water is softer on your eyes, skin, hair and your clothing than the water in regularly chlorinated pools. The chlorine that is created by a salt water chlorination system is produced by converting dissolved salt into a liquid form of chlorine which won’t produce the smell that we normally associate with this chemical. We’ll discuss this topic in more detail below.
So if you’d like to swim in a pool where you can open your eyes and don’t have to worry about the strong smell on your body and clothes afterwards, these are just two benefits of a salt water pool.
Can You Open Your Eyes In Salt Water With Contacts?
Being a contact lens wearer myself, it’s not a good idea to open your eyes under water with contact lens regardless of where you’re swimming unless you’re wearing goggles or an underwater mask.
First off, the contact lenses may get washed away or at least move far enough from the front of your eyeball that you can’t see properly or can’t remove the lens.
Secondly, there is a chance that some bacteria or other debris gets behind the lens and stays there, irritating your eye or worse, causing an infection if you wear extended wear lenses.
If you wear contact lens and want to open your eyes under water wherever you’re swimming, always wear airtight goggles or a mask.
Salt Water Pools Have Very Little Salt Content
So salt water in a pool has a very low level of salt, just enough to keep the pool water sanitized. It won’t burn eyes or irritate skin. Another great health benefit is that the chlorine that is produced in a salt water pool is sodium hypochlorite which doesn’t have the associated strong smell that often get on your skin and clothes after swimming in a chlorinated pool.
How safe is sodium hypochlorite? The CDC has written about it in terms of its use to not only sanitize pool water but drinking water too:
Investigations have shown sodium hypochlorite to be an effective disinfectant having broad applications. Although a number of other disinfectants (calcium hypochlorite, ozone, UV, solar disinfection) and treatment processes (filters, slow sand filtration) have been investigated, sodium hypochlorite appears to offer the best mix of low cost, ease of use, safety, and effectiveness in areas where there is enough water to drink and water is not excessively turbid.
CDC
Chlorine Is Still Used In A Salt Water Pool
It’s sometimes believed that having a salt water pool means you never use chemical chlorine but this is incorrect. Chemical chlorine is still used occasionally to open salt water pools in the spring when existing chlorine levels are very low and when closing the pool in the autumn to help prevent the spread of algae over the winter.
Chemical chlorine can also be used sparingly during the summer pool season to shock the pool, quickly raising the chlorine level during periods of heavy pool use, hot summer weather and heavy rain all of which contribute to killing chlorine and potentially de-sanitizing the pool.
Does Salt Water Pool Water Dry The Skin?
Chlorine pools are known for not only irritating the eyes – who hasn’t had bloodshot eyes at least once as a kid after a day in the pool – but also for irritating the skin. Chlorine can additionally dry the skin with significant exposure. Between the smell that pool chlorine gives off combined with the drying ability, it’s no wonder we were always told as kids to have a shower after swimming by our parents.
Salt water pools don’t experience the same thing however. Most people will have no trouble opening their eyes in pool water and won’t experience dry skin. Again, the salt content in the pool is very low, is just enough to keep the pool clean and doesn’t have a skin drying side effect like chemical chlorine.
Salt Water Chlorination System
A salt water chlorination system is made up of several components.
The chlorination system itself which manages the processes and offers a number of features typically including a pump timer, salt level monitoring, water flow sensor and other automation features to minimize the manual work you need to do to keep the pool running.
But the actual part of the chlorination system that creates the chlorine is the salt cell. It’s a plastic tube that contains electrified titanium plates internally, that fits directly into the existing piping of your pool system. Water passes from the filter, through the pump and through the salt cell where the salt is converted into chlorine. The water then returns to the pool through the return jets as chlorinated, clean water. It’s a continuous cycle of old water getting filtered, rechlorinated and sent back to the pool again.
Salt Water Usage In Your Pool
The amount of salt used in a salt water pool every year is fairly insignificant. While a chlorine pool may require $300 – $800 per year in liquid chlorine, a salt water pool may only require $50 of salt each year. While you can buy a 20 lbs bag of pool-specific salt for about $35, you can also use white salt pellets used in a water softener. You can pick up a 40 lbs bag of water softener salt for $10 or less. You may only require 2-4 bags that size to keep your salt water pool running for one pool season.
If you have a water softener, you can just buy an extra bag or two of white salt pellets and keep them in stock for both the softener and pool. Follow the manufacturer suggestions as to what type of salt you should use for your chlorination system and avoid the clear crystal salt as it is harder and doesn’t dissolve as well. I’ve used regular white salt pellets for years for our Hayward AquaRite chlorinator system with no trouble.
Other Salinity Levels
Here are examples of salt levels in various liquids:
- Fresh water – Less than 1,000 ppm
- Slightly saline water – From 1,000 ppm to 3,000 ppm
- Salt water pool water – From 2,700 ppm to 3,400 ppm
- Moderately saline water – From 3,000 ppm to 10,000 ppm
- Human tear – 9,000 ppm
- Ocean water – 35,000 ppm
Conclusion
A salt water pool is unlikely to cause eye or skin irritation in most people since the salt level is very low, about 1/10 what you find in the ocean. Additionally, the chlorine produced in a salt water pool doesn’t come with the associated strong smell that chemically chlorinated pools have. A salt water pool also has the advantage of generally being easier to maintain in terms of water chemistry than a chlorine pool.