Despite what you might think, a salt water pool does use chlorine. A salt chlorinator is installed to convert salt that is added to the water into chlorine that is used to sanitize the water and keep it clean for swimming.
A salt water pool requires a chlorine level measured in parts per million of 1 ppm – 3 ppm just like a regularly chlorinated pool. A salt chlorinator converts dissolved salt to chlorine albeit a softer form that doesn’t come with the associated smell that is hard on the skin and eyes.
Let’s take a closer look at testing, measuring and adding chlorine to a salt water pool.
How to test chlorine in a salt water pool
Chlorine is tested in a salt water pool the same way as a chlorine one: You can use a home test kit, pool testing strips or take a water sample to your pool company for them to check it.
Some higher end chlorinator system manufacturers such as Hayward offer a Sense & Dispense feature which for about $700 added to the cost of the chlorinator, automatically tracks and adjusts chlorine and pH for you. This can reduce the overall work and maintenance of your pool while also decreasing chemical costs if you allow the computer to run things for you.
For test strips, you can purchase salt pool specific ones that additionally measure the salt level in the water although quality chlorinator models measure that for you.
Can you add liquid or powder chlorine to a salt water pool?
You can and will add chlorine manually to a salt water pool. Liquid chlorine or shock powder is usually added in the spring as you are opening the pool and again as you’re closing it to give it one final bump to keep algae at bay when you shut the system down for the winter.
Some salt water pool owners will additionally shock the pool throughout the hot summer months when pool usage is heavy and the sun is bright. Chlorine dies quickly due to the UV rays from direct sunlight and pool usage naturally uses up chlorine too as humans track body oils, sweat, lotions and other contaminants into the water.
If your dog swims in the water regularly, it tracks fur, dander, feces (yep) and other debris into the water, too.
Salt water pools still require chlorine to operate. The salt chlorinator system converts dissolved salt into chlorine using electrolysis by way of the salt cell. The resulting chlorine is softer on clothing, skin and eyes than chemical chlorine in liquid, powder or puck form but it’s still chlorine. Chlorine is the sanitizing (cleaning) agent used in both chlorine and salt water pools. The delivery of the chlorine is different however.
Whereas a salt water chlorinator produces chlorine from salt, a regularly chlorinated pool uses chemical chlorine that is added regularly to the water. A salt water pool uses salt but a regularly chlorinated pool does not.
What is the Super Chlorinate feature used for?
The Super Chlorinate feature on some Hayward salt water chlorinators is one that overrides whatever settings you have and will run the chlorinator at 100% capacity for a period of time to bump up chlorine production. Other chlorinator manufacturers may use different names for this chlorination booster feature.
Chlorine can only be produced when the pump is running so if you set the chlorinator to run 8 hours per day and set the Super Chlorinate feature to run for 24 hours, you would produce chlorine 100% of the time during that 8 hour run time. If you ran the pump 12 hours that day, it will produce chlorine for 12 hours straight.
The Super Chlorinate features is a convenient aspect of your salt water system but it does come with a cost: Each salt cell only has a certain lifespan and the more you use it the sooner the cell will have to be replaced. Hayward even tells you up front how many pounds of chlorine each salt cell should produce during its lifetime.
It’s also worth noting that even running the Super Chlorinator feature for 24 hours straight at 100%, you’re only producing a relatively small amount of chlorine during that time compared to what you could add to the water if you used a commercial chlorine product.
So while you can use the Super Chlorinate feature it does use up your salt cell’s total available production. An alternative even for salt water pool owners is to shock the pool instead.
How do shock your salt water swimming pool?
Shocking your pool refers to adding a large or concentrated amount of chemical chlorine typically in liquid or powder format for the purpose of quickly raising the chlorine level in the water.
Even a salt water pool can benefit from shocking the pool from time to time during the pool season when the pool is being used and with the combined effects of direct sun and heavy rainfall, the chlorinator may have trouble keeping up with demand. Shocking the pool quickly raises chlorine levels to keep them in range.
Even if chlorine becomes a bit high, it will always start trending downwards again with pool usage, sun and other factors.
NOTE: It is important not to quickly dump highly concentrated liquid or powder chlorine into the skimmer of a salt water pool because it will quickly get pumped through the salt cell. Highly concentrated amounts of chlorine like this can damage the cell over time.
Liquid chlorine is usually best poured into the deep end or throughout the pool with the pump running. Powdered chlorine is best added to a bucket of warm water and mixed into a slurry and then slowly poured throughout the pool. A chlorine puck is usually put into the side skimmer basket and allowed to slowly dissolve over time.
Follow the product directions of your chosen brand in case instructions are different.
How to shock a salt water pool with bleach
While you can use bleach to shock your pool, you have be careful about the dosing amount and also the strength of the bleach being used. Bleach is highly concentrated and will of course – as the name would suggest – bleach your liner if you pour it in concentrated form too close to the walls of the pool.
I’ve never personally used actual bleach in a pool full stop and have only used concentrated powder shock and liquid chlorine.
Using chlorine in a salt water pool for a quick boost
Chlorine addition by liquid, powder or puck form quickly raises the chlorine level in a pool when you need a boost. Common reasons for shocking a pool include:
- Heavy pool usage and many swimmers using it.
- Effects of UV from the direct rays of the sun.
- Heavy rainfall which dilutes chlorine and other chemicals in the pool.
- Draining water from the pool when it’s too high for another reason such as when you are trying to dilute another water factor.
Salt water pool considerations to think about
There are several main types of pool styles to choose from but not all are suitable for a salt water system.
Here are the main types of salt water pools that exist along with comments regarding their suitability to use a salt system.
Concrete pool: A salt water system is not recommended for a concrete pool without first knowing the pitfalls. With any concrete pool, they require more maintenance than other styles especially as it must be resurfaced from time to time. This of course means emptying the pool of its water, resurfacing it and then refilling the pool and balancing the water all at great expense to you.
Salt is additionally very harsh on concrete, much more so than regular chlorine. This means you’ll likely be resurfacing your concrete pool more frequently.
Many pool builders won’t even install a concrete pool with a salt water system as a result.
Vinyl liner pool: Many salt water chlorination systems are built with vinyl liner pools so it’s commonly done. A vinyl liner can be expected to last many years – 10 to 15 years isn’t out of the question. Salt-produced chlorine tends to be less harsh than commercial chlorine but salt water can however damage metal so don’t be surprised if you find rust stains on your metal ladder after several years of use.
While salt water can damage pool equipment, if you keep water chemistry in line you should have no difficulties to worry about with a vinyl liner pool.
Fiberglass pool: Why did boat manufacturers start building boats made of fiberglass decades ago? Fiberglass stands up very well to salt and is a very durable material in general. A fiberglass pool is ideal for a salt water pool system as the surface is non-porous and thus very compatible. As a side note, they also come in many styles and colors.
In addition to their high quality look and no liner to replace or concrete to resurface, fiberglass pools are becoming a more popular choice for pool owners.
