Lithium Hypochlorite: Should You Use It In Your Pool?



Swimming pools require round the clock care, especially when it comes to the quality of their water.

The use of sanitizing chemicals is vital to healthy pool water, and there are various routes you can take. Depending on your pool type, chemicals such as chlorine, bromine, biguanide, and salt can be used as sanitizing agents.

There are a few types of sanitizing hypochlorites, and lithium hypochlorite is one of them.

Note: Lithium hypochlorite is no longer available as a swimming pool sanitizer due to a short supply of lithium.

What Is Lithium Hypochlorite?

Lithium hypochlorite (LiClO) is a granular powder chlorine. It has 28 – 35% free available chlorine (FAC) and can be used as a swimming pool sanitizer, spa sanitizer, or shock treatment. It’s also unstable, which means it’s pure chlorine and doesn’t contain any cyanuric acid (aka pool stabilizer).

Compared to other chlorines like calcium hypochlorite (cal-hypo), lithium hypochlorite’s finer consistency makes it well-suited for fiberglass pools or those with a vinyl liner. As the chlorine is easily dissolved, it leaves behind zero granules that could potentially burn through these surfaces.

Lithium hypocholorite’s high solubility also makes it an excellent shock treatment chlorine and it won’t raise the pH level of the pool. Also, unlike cal-hypo, it contains zero calcium. This means you won’t get elevated calcium hardness levels in your pool that lead to issues with hard water

However, it’s not all sunshine and rainbows when it comes to lithium hypochlorite. It has a relatively low FAC level, and it’s also a lot more expensive compared to a high FAC and cheaper chlorine like cal-hypo. 

Lithium Hypo Quick Stats

  • 28 – 35% Free Available Chlorine
  • Unstabilized form of chlorine
  • Alkaline pH level of 10.8
  • Highly soluble making it ideal for fiberglass and vinyl liner pools
  • Can be used as pool/spa sanitizer or shock treatment
  • Won’t raise pool’s pH level
  • Contains zero calcium
  • Most expensive chlorine

How Does Lithium Hypochlorite Work?

A chemical reaction takes place whenever chlorine is added to water, and lithium hypochlorite is no different.

Once dissolved, lithium hypochlorite turns into hypochlorous acid and hypochlorite ion, more commonly known as free available chlorine. FAC goes on to sanitize the pool water, removing harmful microorganisms and bacteria that may be present.

When FAC attacks pollutants, it latches onto them. FAC is now in a state of combined chlorine, which is also known as chloramines. A dead giveaway of a dirty pool, chloramines is that potent chlorine smell, which is a gas and a harmful irritant for humans.

As chlorine is perpetually sanitizing the pool, chloramines continually build up until they’re removed through oxidation. Adding a mass dose of chlorine (shocking the pool) will do this, or you can use a non-chlorine pool shock which is an oxidizer that neutralizes the chloramines.

Lithium hypochlorite is also an unstable chlorine. This means it doesn’t contain any cyanuric acid (CYA). Stabilized chlorines contain CYA, which protects the chlorine from breaking down quickly due to the sun’s UV rays. With lithium hypochlorite, you’d need to add in CYA to prolong it’s lifespan.

The Pros And Cons

So what are the upsides and downsides of using lithium hypochlorite?

Benefits of Lithium Hypochlorite

  • It won’t raise the pool’s pH level. Hypochlorites (sodium hypochlorite, calcium hypochlorite, and lithium hypochlorite) will won’t raise your pool’s pH level long-term. There will however, be a temporary increase in the pool’s pH level due to the alkaline nature of chlorine. But over time the pH will return to normal due to the breakdown of the chlorine during the sanitization process.
  • It’s highly soluble. This makes it easy to add straight to the pool water, or dissolve in a bucket before pouring the solution into the pool. The fine-powder consistency also means it won’t burn delicate surfaces like fiberglass or vinyl.
  • It doesn’t add calcium to the pool. Increased calcium levels result in hard water scaling that leaves deposits on your pool walls at the water line, and can cover surfaces in a white residue. The only ways to remove calcium from the water is through the addition of pool flocculant/clarifier or draining the pool.

Drawbacks of Lithium Hypochlorite

  • It’s not cheap. One of the reasons lithium hypochlorite isn’t a commonly used chlorine is because it’s expensive. With the amount of chlorine that pools require over the course of a swim season, it’ll be quite costly to use lithium hypochlorite.
  • It has a relatively low FAC level. Not quite as low as the 10 – 12% FAC that sodium hypochlorite has, lithium hypochlorite’s 28 – 35% FAC level is no match for calcium hypochlorite, which ranges from 40 – 78%! This means you’ll use less cal hypo and get better performance from it. Couple that with cal hypo’s affordable price and it’s a virtual no brainer why it’s the go-to unstabilized chlorine.
  • It’s unstable. No, not unstable like your crazy ex, but rather it doesn’t contain CYA. Pool stabilizer like CYA acts as a sunblock for chlorine, protecting it from the sun’s UV light. Without CYA in the water, chlorine gets fully destroyed by the sun in a matter of hours. So if you’re using an unstable chlorine like lithium hypochlorite, you’ll have to add an additional chemical to keep the chlorine protected.

Should You Use It In Your Pool?

If lithium hypochlorite sounds right for you, surprise! It’s no longer available.  

This is due to the increased demand of lithium for things like lithium-ion batteries, as well as its use in the production of metal and glass. 

While the amount of lithium in lithium hypochlorite is small, an increased price for the chemical has made this already expensive chlorine even pricier.

If you’re looking for a similar shock, we’d recommend going with a chlorine-free oxidizing pool shock, or look at other options such as dichlor or cal-hypo, including liquid chlorine or tablets for regular chlorination.

Lithium What Now?

While lithium hypochlorite is no longer in production, it shouldn’t hinder you from finding a suitable substitute for your pool. 

With a range of choices, you can still keep the water clean and it will be cheaper than if you used lithium hypochlorite.

Categories: Pool Care, Pool Chemistry