A saltwater pool converts salt into chlorine, so it’s not all that different from a traditional chlorine-based pool. In fact, the only difference between the two is how chlorine is delivered to the water.
However, adding more chlorine can sometimes be beneficial. This article will look at why you might want to add chlorine to a salt pool, how much you should use, and how to go about adding it, step-by-step.
Quick answer: Yes, you can add chlorine to a saltwater pool. You shouldn’t need to do it very often, but there are special circumstances where manually adding chlorine to your water (particularly liquid chlorine) is advised.
Why Would You Add Chlorine to a Salt Pool?
A saltwater pool already generates its own chlorine, but your salt generator won’t always be running. And even when it is, it’s not going to make chlorine at a particularly fast rate.
As such, some situations will require you to add another source of chlorine to maintain proper sanitizer levels, if only temporarily.
Here are some examples:
Low chlorine production. You accidentally had your saltwater generator running too low, or perhaps it’s just not working correctly. In those cases, you might be caught off guard with too little chlorine in your water.
High pool usage. The more people using the pool, the more sweat, saliva, lotions, and other human nastiness goes into the water. This uses up more chlorine than usual, which can cause your generator to come up short.
Environmental factors. In the same way swimmers introduce contaminants to the water, environmental factors like wind and rain also bring debris and other unwelcome substances that get your chlorine riled up.
Algae growth. The presence of early-stage algae is a clear sign of your chlorine levels being too low. The most effective way to deal with it is to add a ton of chlorine in order to shock (super-chlorinate) your pool.
Water change. If you’re filling a new pool or draining and refilling an existing pool, the water will have little to no chlorine content. Initially, you’ll need to throw a decent amount of chlorine at it to reach a suitable level.
Opening or closing. Whether you’re opening or closing your pool, seasonal changes often call for a heavy injection of chlorine.
How Do You Know If More Chlorine Is Needed?
Even under heavy loads or incorrect settings, your pool may still be able to hold its own without an additional source of chlorine.
It’s always a good idea to test your water before making the assumption that more chlorine is required, as your chlorine level may still be adequate and you could just end up over-chlorinating your water.
As long as you maintain your target minimum free chlorine reading, you don’t need to worry about adding more chlorine.
This minimum will be different for every pool because it largely depends on your waters’ cyanuric acid level. Saltwater pools also tend to target a lower minimum because they receive chlorine at a more constant rate compared to traditional chlorine pools.
You can use the table below to figure out your target chlorine level, and please remember these numbers only apply to saltwater pools:
|Cyanuric acid level||Min. chlorine level||Ideal chlorine level|
|20-29 ppm||2 ppm||3-5 ppm|
|30-39 ppm||2 ppm||3-6 ppm|
|40-49 ppm||2 ppm||3-7 ppm|
|50-59 ppm||2 ppm||3-7 ppm|
|60-69 ppm||3 ppm||4-9 ppm|
|70-79 ppm||3 ppm||5-10 ppm|
|80-79 ppm||4 ppm||6-11 ppm|
|90-99 ppm||4 ppm||6-12 ppm|
|100+ ppm||5+ ppm||7+ ppm|
Remember, you only need to think about adding more chlorine if your free chlorine level has dropped below your target minimum.
What About Ramping Up Your SWG Settings?
It’s likely your saltwater generator has a “super chlorinate” or “boost” setting to really ramp up the production of chlorine.
This can be a useful setting when dealing with minor deficiencies in your free chlorine level, but it’s not going to work when you need a faster and more significant boost in chlorine.
Salt generators simply aren’t able to produce chlorine all that quickly, even on high settings, and any delay in getting back to your target chlorine level is going to give contaminants like algae an opportunity to take hold.
Manually adding chlorine allows you to very quickly get your free chlorine reading to an adequate level, and regain protection.
While you could increase the settings on your generator and add chlorine at the same time, this makes calculating the amount of chlorine to add more difficult and just isn’t worth the hassle.
What Types of Chlorine Can You Add?
Assuming more chlorine is needed, you need to decide what type or form of chlorine you’re going to add to your water.
There are three main options, each with its own pros and cons:
- Chlorine tablets offer a slow-release method of chlorinating your water. They’re most commonly found as stabilized chlorine (trichlor or dichlor) but can also be found unstabilized (calcium hypochlorite).
- Granular chlorine is essentially an uncompressed version of chlorine tablets, meaning it’s also often stabilized (trichlor or dichlor), but allows for a must faster release of chlorine.
- Liquid chlorine, or bleach, is an unstabilized form of chlorine (sodium hypochlorite) that typically comes in 1-gallon jugs. Like granular chlorine, this provides a fast-acting solution to significantly raise your chlorine level.
Which Type Should You Use?
We strongly recommend liquid chlorine for this.
Liquid chlorine allows you to quickly raise your free chlorine level without introducing additional stabilizer (cyanuric acid) or calcium into the water.
These “additives” can quickly become problematic for a salt pool (even in moderate concentrations) and are notoriously difficult to fix without partially or sometimes even fully replacing the water.
What’s more, unlike tablets or granular chlorine, liquid chlorine will only have a small and short-lived impact on your pool’s pH level, making it effectively pH-neutral.
How to Add Chlorine to a Salt Pool (3 Easy Steps)
Manually adding chlorine to a salt pool is pretty straightforward, and hardly differs from how you would approach a non-saltwater pool.
Let’s walk you through the process:
1. Test Your Water
It’s impossible to know exactly how much chlorine you need to add unless you know where you’re starting from.
Testing your water with a liquid testing kit will give you the most accurate reading, but you can also get by with a test strip. If you’re not sure how to properly test your water, we have a guide you can follow here.
Specifically, you’ll need to take note of:
- Your current cyanuric acid level
- Your current free chlorine level
2. Calculate the Required Amount of Chlorine
Just like with a traditional chlorine pool, you’ll need to add enough chlorine to reach your minimum target free chlorine level.
If you don’t know your target, refer to the section above before moving on.
For this part, you’ll need to know your current free chlorine reading and the exact type of chlorine you’re using (along with its % of chlorine concentration).
Then, use the calculator below to get an exact measurement:
Note: We’re not including chlorine tablets here because they’re slow-dissolving and therefore not suitable for this particular use case.
3. Prepare and Measure Out Your Chlorine
This part will vary a lot depending on the type and brand of chlorine you’re using, so it’s best to refer to the packaging instructions for your specific chlorine product.
For example, liquid chlorine can be added directly to the water as it’s already dissolved, but you’ll need to pour it into a measuring jug to get the correct dosage.
Granular chlorine is usually pre-dissolved in a bucket before being added to the water. It can also be sprinkled in straight from the packet but this can be harder to measure when aiming for exact dosages.
Note: Safety gear is important when handling all types of chlorine. Be sure to wear protective gloves and eyewear during this step.
4. Add the Chlorine to Your Water
Once you’ve measured out your liquid chlorine or granular chlorine, you can go ahead and add it to your pool water.
Ensure your pump is running and there’s good circulation in your pool, and try to pour the chlorine near an active return jet. You can also leave your salt chlorine generator running during this part.
It should only take around 30 to 60 minutes for the chlorine to disperse, at which point you can turn off the pump if you wish.
5. Test Your Water Once More
As annoying as it is, you really should test your water once more to make sure you calculated your dosage correctly.
If everything went to plan, you’ll be at or slightly above your target chlorine level and there will be nothing more for you to do.
If your free chlorine level is way too high, wait for it to drop a little before using the pool — but keep in mind you can safely swim at surprisingly high chlorine levels.
If it’s too low, go through steps 2-5 again.
The Bottom Line
Saltwater generators do an amazing job at keeping your free chlorine level in check, but even they can fall short under the right circumstances.
Fortunately, if your salt generator needs some assistance, manually adding other forms of chlorine will help to get back on track. Liquid chlorine is especially suitable in cases like this, but short-term use of granular chlorine works too.