Should You Add Borates to Your Pool Water? (Pros and Cons)



Some pool owners choose to put borates in their pool water, but do the benefits outweigh the drawbacks?

If you’ve wondered whether it’s worth adding borate to your pool, or what the potential consequences are of doing so, this one is for you.

What Are Borates?

Borate is a mineral commonly found in nature.

Unless you’ve intentionally added borate to your pool, however, it’s unlikely you’ll have any borates in your water.

The ideal level of borate in pools is 30 to 50 parts per million, though you certainly don’t need any to have a well-functioning pool.

Benefits of Adding Borates to Pool Water

Below are the benefits of adding borates to a pool:

They Act as an Additional pH Buffer

When you think of a pH buffer, you think of total alkalinity.

Total alkalinity absorbs changes in the water to prevent wild fluctuations in your pH level. In reality, though, alkalinity mostly absorbs negative changes in pH as it buffers against acid.

Borates buffer in the opposite way because they absorb positive changes in pH which slow the natural rise of pH in a pool, allowing you to add acid less frequently.

This is particularly beneficial if you own a saltwater pool as the overall lower pH prevents scaling inside the cell plates of your saltwater generator.

They Offer Protection Against Algae

Borates work as an algaecide to prevent and slow algae growth.

You would need a ridiculous (and frankly unsafe) level of borate in your water to completely eliminate chlorine, but a safe level will certainly aid chlorine in the fight against green algae, yellow algae, and even black algae.

Of course, this also reduces chlorine consumption by some degree as it’s not being used up fighting algae all by itself.

The amount of reduction depends on how prone your pool is to algae. For example, if your pool is constantly fighting algae blooms, borates will have a more meaningful impact on your chlorine consumption.

They Make Your Water Feel Smoother

Ever been in a pool with a soft, silky, or smooth water texture?

Well, chances are, that’s borates at work.

The addition of borates in your water sets off a chemical reaction, whereby borate binds with calcium and magnesium ions (which make your water hard) and effectively removes them from the water.

It’s worth noting, however, that not all pool owners feel the same softening effect of borates in their pool water, so this one can be a bit hit and miss.

They Give Your Water More Sparkle

Many pool owners also report subtle aesthetic changes to their water after adding borates.

It isn’t properly understood how this “sparkle” or “shine” is created, but it’s likely something to do with how borate interacts with light.

As before, your mileage may vary on this one – but there’s a good chance you’ll see this change in your water if you live in a particularly sunny climate.

Drawbacks of Adding Borate to Pool Water

Below are the drawbacks of adding borates to a pool:

They May Harm Small Pets

The concentration of borates used in swimming pools isn’t harmful to humans, at least not if you swallow the odd mouthful.

The same can’t be said for your cats or dogs, however.

For smaller animals, borates can cause stomach issues if ingested. In fact, it’s not uncommon for this to result in illness or even death after drinking from pool water containing a moderate level of borate.

If you plan on using borates, train your pets NOT to drink from the pool. Besides, the hair and saliva they leave behind only make your chlorine and pool equipment work harder.

They Cost Money

Adding borates can be done using borax, also known as ‘sodium borate’ or ’sodium tetraborate decahydrate’.

This chemical also raises the pH level of your water, so it needs to be paired with muriatic acid in order to counter the rise in pH.

An easier, if not slightly more expensive way to inject borates into your water is to use boric acid, also known as ‘hydrogen borate’. You can also find this in either granular or powdered form.

Either way, expect to pay as much as $100 for all the required chemicals, especially if you’re starting from zero borates.

They Don’t Break Down In Water

Borates don’t evaporate or break down in water.

In fact, the only way to realistically remove them from your water is to drain and refill your pool – much like with cyanuric acid, calcium, or metal content such as iron and copper.

On one hand, not accounting for splash out and backwashing, this means you’ll almost never need to top up on borates.

On the other hand, it means getting rid of borates completely is going to cost you a complete refill, that is if you happen to change your mind about having them in your water.

They May Be Prohibited In Your Area

Depending on where you live, you may not actually be allowed to use borate in your water.

For example, the EU banned borates in all cosmetics due to health concerns, and there are some laws in the United States that make it very difficult to import products containing borates.

While unlikely, it’s worth checking the laws in your area if you’re not sure.

Bottom Line: Borates Are Your Friend

Despite some drawbacks of adding borates to your pool water, most pool owners would agree they’re easy to overcome.

When you factor in all the upsides, including extra pH buffering, more protection against algae, less chlorine consumption, and smooth, sparkly water – it’s simply too good to pass up.

Categories: Pool Care, Pool Chemistry