Liquid Chlorine vs. Chlorine Granules

Pool ownership requires a lot of upkeep — and a lot of choices. Everyone who’s spent a summer afternoon floating in a pool knows that there’s chlorine in play, but not as many people know that there are many chlorine options on the market, each with their own advantages and drawbacks.

As a pool owner, though, it’ll be up to you to decide just what kind of chlorine you want to cleanse your pool water and keep your pool clear and germ-free.

Two Types of Chlorine

Chlorine is a familiar product to anyone who’s been in a pool, but how does it work? When you add chlorine to a pool, its reaction to the water creates hypochlorous acid, a cleanser that kills common germs, viruses, and bacteria, from E. coli to swimmer’s ear.

There are a couple of different chlorine types, but they both accomplish the same goal of cleansing your pool water. The two main chlorine varieties are liquid chlorine and chlorine granules.

Similarities

Both types of chlorine have the same goal of clearing your pool of unwanted guests so you can swim in peace, so they have a lot in common.

Both liquid and granular chlorine:

  • Are highly concentrated chlorine
  • Are responsible for taking care of any germs, bacteria, and algae that might be in your pool
  • Help keep your pool crystal clear

Outside of these similarities, you’ll find mostly the same products with a few differences under their different manufacturing processes.

Differences

These two products also have some key differences, so you’ll need to make your choice as a pool owner.

Liquid chlorine:

  • Is more commonly used
  • Is often much cheaper
  • Is refillable
  • Mixes easily with water
  • Does not leave any buildup behind

Chlorine granules:

  • Have a longer shelf life, meaning you can store it
  • Dissolves in water
  • Easy to transport
  • Are often stabilized
  • Have a lower pH value

What is Liquid Chlorine?

Liquid chlorine (sodium hypochlorite) is a highly-concentrated form of chlorine made by compressing the chlorine gas with caustic soda to produce a liquid product. Liquid chlorine is even more concentrated than other kinds of chlorines because of its production.

Liquid Chlorine Pool Shock (Case - 4 Gallons) - 12.5% Sodium Hypochlorite
  • ✅ Premium Swimming Pool Shock - NSF/ANSI 60 Certified
  • ✅ Product Does Not Cloud Pool
  • ✅ Ready To Use, No Mixing Required - Great Choice for Pool Closings
  • ✅ Perfect For Pressure Washing, Sanitation & Other Related Uses
  • ✅ 12.5% Commercial Grade Strength Liquid Chlorine - USA Made - EPA Registration No. 55852-3

When You Should Use It

While liquid chlorine is popular with many home pool owners, it’s best for larger pools with many swimmers because of its large-quantity containers. It can also be the right choice for smaller or private pools that get a lot of use and need more regular chlorination.

Because of the way manufacturers produce liquid chlorine, it also has a couple of downsides that might outweigh its benefits for home pool owners.

Liquid chlorine has a high pH of 13, so you need to add more acid, typically cyanuric acid, to your pool to counteract the high pH and keep it protected in the sun.

Because of its manufacturing process, it’s also a potentially damaging product for your home pool. It can erode pool walls and tiles, so you need to be careful when chlorinating your pool with liquid chlorine. If you do use it, just make sure to add it to water first to lower the pH.

What are Chlorine Granules?

Chlorine granules, also called powder chlorine or shock, are the solid form of chlorine. Manufacturers often make powder chlorine by using chlorine gas to treat lime.

These types of chlorine dissolve quickly, but you have to make sure the granules dissolve entirely. Otherwise, they can leave residue or buildup on your pool walls and tiles.

Chlorine granules themselves have a few different varieties: calcium hypochlorite, lithium hypochlorite, and dichlor. Calcium hypochlorite is another low-cost chlorine solution, but it comes with the same issues that liquid chlorine has with a pH of 12, requiring additional treatment.

Lithium hypochlorite is another fast-dissolving, easy-to-use powder chlorine variety. It dissolves fast and leaves a pool that’s clear and free of residue, and best of all, you can swim in it right away. The bad news is lithium hypochlorite is harder to find than the other varieties.

Dichlor is sodium-based chlorine powder with a pH of 7, meaning it can go straight into the pool without adding additional products. Its sodium base makes it an excellent choice for quick dissolve with no cloudiness or residue.

It’s also safe to use in all types of pool interiors, from plaster to paint, making it an excellent choice for home pools and spas of all kinds, including above ground.

In The Swim Calcium Hypochlorite Chlorine Granular Pool Shock - 25 pounds
  • Powerful chlorine shock treatment that is great for regular maintenance
  • Main active ingredient is 68% Calcium Hypochlorite (Cal-Hypo) for quick sanitizing
  • Must pre-dissolve/dilute to prevent bleaching of vinyl liner surfaces
  • Dosage: 1 Pound per 10,000 gallons
  • NOTE: A valid phone number is required to ship this item, you must be present to sign for delivery

When You Should Use Them

Chlorine granules of either kind are an excellent choice for private pool owners because they don’t require as much outside product use as liquid chlorine often does.

Chlorine granules, especially dichlor, have a lower pH than liquid chlorine, so you can mix them into your pool water without having to add acid. If you’re looking for a quick, all-in-one product, chlorine granules are a great choice if a little bit more expensive.

The real downsides to chlorine granules are their price and their smaller amounts. Liquid chlorine has an advantage in being cheap and sold in bulk, while liquid chlorine, especially dichlor, is typically higher cost and sold in small containers.

Aside from these drawbacks, chlorine granules are an excellent choice for small, private pools for typical use.

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Final Thoughts

No matter what type you buy, chlorine is still going to help kill the bacteria, germs, and viruses in your pool and clear out algae, all while keeping your pool looking nice and clear.

You’ll need to consider whether you want to buy extra ingredients to mix with the chlorine as you’ll need to with liquid chlorine to counteract its base, or whether you want to pay a little more to have a product that doesn’t have a high pH.

You should also consider the size of your pool. Are you trying to treat a small pool or spa? Powder chlorine, especially dichlor, will be an excellent choice for that. If you have a larger pool or host frequent pool parties, liquid chlorine might be a better choice for you.

Each product is great for pool owners of either kind. But they both come with their drawbacks, depending on your preferences.

Questions? Drop us a line. Also be sure to read our guide on swimming pool maintenance 101 and pool chemistry.

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