If you have a layman’s understanding of how a saltwater pool works, you’d know that it uses a salt chlorine generator to convert salt into chlorine. While this process is mostly automated and hands-off, what you may not have realized is that you may occasionally need to add additional chlorine to your saltwater pool.
Some common cases are when the pool is being opened after a long period where it was not in use, in the summer during periods of frequent use, after heavy rain or wind, and when the chlorinator is not generating enough chlorine due to a malfunction. If your saltwater pool’s free chlorine levels are below 1 ppm, then you need to add chlorine to increase the free chlorine level back to a safe range.
In this article, we’ll discuss the various situations where you might want to add some chlorine to your saltwater pool, the kinds of chlorine you can add, and how much you should add.
Can you add chlorine to a saltwater pool?
Some people may hold the mistaken belief that salt should only be added to a saltwater pool. After all, it’s literally called a saltwater pool. If you also need to add chlorine, then what difference is there between saltwater pools and chlorine pools?
Conceptually, they are quite similar. To be frank, both are chlorine pools. The difference is that saltwater pools have a salt-chlorine generator, or chlorinator for short, that converts salt in the water to chlorine.
Ideally, the chlorinator will only generate as little chlorine as needed so that there is only the bare minimum amount of chlorine in the water to kill harmful bacteria and algae in the water that is turning it green and unclean. This should hopefully decrease the severity of the side effects of chlorine such as irritated eyes, skin, and hair.
At the end of the day, saltwater pools still use chlorine to sanitize the water. They are also chlorine pools despite the name; you just happen to add salt into the water more often than you do chlorine.
That is also why, if the chlorine levels are low in a saltwater pool for whatever reason, it is reasonable to add additional chlorine to increase the chlorine concentrations to a safe range.
Conversely, sometimes owners of chlorine pools like to add salt into their pool because they like how saltwater feels silkier and more luxurious. There’s no reason why you can’t add both salt and chlorine in either pool type as long as you know what you’re doing.
When should you add chlorine to a saltwater pool?
As mentioned, there are a few specific instances where you are required to add chlorine to your saltwater pool. They are:
When the pool is opened after a long period of inactivity
When the weather starts getting colder, the pool requires less chlorine since the temperatures are lower and the pool is covered up, thus less chlorine is evaporating or getting used up.
Once the weather starts warming up again in the spring, the pool will have used up all of its chlorine. In order to make the water safe to swim in again, you need to shock the pool by adding in a large amount of chlorine.
Then you can leave the rest up to the salt chlorine generator as it monitors the chlorine concentration of the pool and keeps the water chemistry in line.
During periods of frequent activity
Chlorine can quickly get used up if lots of contaminants are entering the pool or if it is exposed to the sunlight. Chances are both are happening, and in the summertime, happening quite often.
Your chlorinator may not be able to keep up with the chlorine demands of a highly active pool. Sometimes the pool system requires a little bit of help to maintain safe chlorine levels, and that’s where you can occasionally add some chlorine on the side to help out.
Otherwise, low free chlorine levels will allow bacteria to grow and spread, and that will have adverse effects on your health.
When the chlorinator malfunctions
Every saltwater pool owner’s nightmare is when their chlorinator malfunctions. Saltwater pools are marketed as being very cost-effective because of how low maintenance they are.
But if the generator breaks, there are no user-serviceable parts, so you’re going to have to call in an expert. And that costs a lot of money.
In the meantime, what are you going to do? If you still want to use your pool until the technician arrives, you will need to manually add the chlorine yourself to keep the water chemistry balanced.
The good news is that I rarely need to add chlorine to my saltwater pool. The bad news is that adding chlorine can potentially bleach your pool liner or damage the chlorinator salt cell if too much is added.
What kinds of chlorine can you put in a saltwater pool?
There are various types of chlorine, so which ones should you add to your saltwater pool?
You can add chlorine tablets to your saltwater pool, but make sure to wear gloves and to avoid direct contact with your skin. It’s a concentrated chemical and can cause chemical burns.
Additionally, you must follow the instructions with regards to the dosage you need to use. I’ve had a pool company recommend that I put it in one at a time into the skimmer basket.
They also suggested I put the chlorine tablet inside a sock to decrease the rate of dissolving. You certainly don’t want to just check a few tablets into your pool and let them sink to the bottom as they slowly dissolve where they could stain the pool liner due to how concentrated they are.
You also need to consider your salt chlorine generator. Putting in large amounts of chemical chlorine can damage the salt cell since it was designed to produce its own chlorine without much help from chemical chlorine.
Furthermore, if you have a pool heater, you need to be careful with the chlorine concentrations as they can damage the seals.
You can also add liquid chlorine to your saltwater pool. As always, care must be taken to ensure that you don’t damage the pool or harm your health.
Don’t pour the liquid chlorine directly into the skimmer, since the large concentration may damage the pump, heater, and chlorinator over time.
Instead, dump the chlorine at the deep end of the pool where it is close to the main drain and can be circulated throughout the system. Make sure the pump is running and set to circulate.
Lastly, you can also use chlorine powder, often sold in small packets called Shock. I recommend following the instructions found on the product.
However, based on my experience, the instructions are almost always the same and involve: filling a large bucket full of pool water, adding in the chlorine powder, stirring it, and waiting for the powder to fully dissolve.
Then pour this mixture into the deep end of the pool. Make sure your pump is running so that it can circulate the chlorine throughout the pool. The water can get temporarily cloudy, but it dissipates as it is distributed through the pool system.
How much chlorine should you add to your pool?
How much chlorine to add depends on the type of chlorine used and how large your pool is. The goal is to maintain free chlorine levels at 1-5 ppm.
Chlorine strength is different between brands, so I don’t want to give out any specific recommendations. Please read the instructions carefully to see how much chlorine you need to add to raise the chlorine level by 1 ppm per 10,000 gallons of pool water.
You can also use this pool calculator to help you figure out the numbers. Remember to err on the side of caution and add a little bit at a time. Test the water frequently to make sure you don’t add too much chlorine.