Biguanide (Baquacil) vs. Chlorine: What’s Right For Your Pool?

Written by Michael Dean
June 14, 2023

biguanide vs. chlorine pool system

When imagining a clean and inviting pool, the main chemical that comes to mind for most people is chlorine. It’s a no-brainer, after all, since it has traditionally been the most widely used type of pool sanitizer available for decades. But you might be surprised to know there are alternatives, such as biguanide. Both chlorine and biguanide have pros and cons, and understanding their characteristics helps you choose the best option for your pool.

In this article, I will dive into the key differences between biguanide and chlorine as pool sanitizers, comparing their benefits, drawbacks, and more.

Main Takeaways

  • Biguanide offers a chlorine-free alternative for individuals with sensitivities or a preference for non-chlorine systems.
  • As a widely used sanitizer, chlorine is affordable, widely available, and has a proven track record for maintaining water quality and safety.
  • Biguanide and chlorine cannot be mixed, so switching to either system should only be made after carefully considering your preferences and budget.
  • Baquacil is a brand of preservative-free polyhexamethylene biguanide, also known as PHMB or biguanide. The brand is often used as a synonym for this type of pool treatment.

What is Biguanide?

Biguanide provides an alternative to traditional chlorine-based sanitizers. The biguanide causes the contaminants in the water to bind and clump together, making it easier for the filter to capture them. Many biguanide brands are out there, but Bacquacil is definitely the most popular amongst pool owners. Bacquacil is known for being gentle on the skin and eyes and is often chosen by individuals allergic or sensitive to chlorine.

Benefits of Biguanide

Biguanide offers several benefits as a pool and spa sanitizing system.

  • Non-chlorine formula: As biguanide is a non-chlorine sanitizing chemical, it is an appealing choice for individuals sensitive to chlorine or those who prefer an alternative sanitizing method.
  • Gentle on skin: Biguanide is a lot less harsh on the skin, hair, and eyes compared to chlorine, which minimizes the irritation and dryness often associated with traditional chlorine-based systems.
  • Reduced chemical odors: Biguanide’s non-chlorine formula helps reduce the strong chemical odors commonly associated with chlorine-based pools (the ones that form as a result of chloramines in the water).
  • Stable: Unlike chlorine, which needs to be monitored constantly, biguanide does not degrade under the sun’s UV rays. Furthermore, it doesn’t degrade or become less effective due to temperature or pH level changes.
  • Doesn’t oxidize metals: Biguanide does not oxidize metals in the water. So, unlike with chlorine, no need to worry about your blonde hair turning green.

Downsides of Biguanide

While biguanide offers some advantages as a pool and spa sanitizing system, there are also a few downsides to consider:

  • Cost: Biguanide tends to be more expensive than traditional chlorine-based systems. The initial purchase cost of Baquacil products, for example, and ongoing maintenance costs might run higher than what you’re used to.
  • Availability: You might find that biguanide products tend to be less readily available compared to chlorine-based alternatives. Some pool supply stores may have limited stock or may not carry biguanide at all, making it slightly more challenging to find and purchase.
  • Doesn’t eliminate all unwanted contaminants: While Baquacil can certainly eliminate the bacteria and algae in the water, this product is not an oxidizer. This means that Baquacil cannot tackle contaminants like sweat, urine, and other bodily fluids. To get rid of those contaminants, you’ll need to purchase the Baquacil Oxidizer, which is an added expense.
  • Cloudy pool water: When using a biguanide, cloudy water is a common concern, as the chemical causes particles to clump together. Occasionally, these clumps may get stuck in the pool filter, so the filter won’t work as well as it should, leading to cloudy water.

What is Chlorine?

Chlorine is a chemical widely used as a disinfectant for swimming pools and other purposes. A strong oxidizing agent, it is highly effective in killing bacteria, viruses, algae, and other harmful microorganisms in water. Chlorine is the most popular pool sanitizing method.

Benefits of Chlorine

Chlorine offers several benefits.

  • Strong disinfectant: Chlorine has been the preferred choice for pool sanitization for a good reason. For one, it’s highly effective at killing bacteria, viruses, algae, and other microorganisms present in water. It’s also really efficient at maintaining a clean and hygienic swimming environment.
  • Wide availability: Chlorine-based sanitizers and products are readily available at pool supply stores, making them easily accessible for pool and spa owners. There are also many types of chlorine to choose from.
  • Cost-effective: Chlorine is generally more affordable than alternative sanitizing systems, including biguanide, and is an economical option for maintaining water quality and safety.
  • Oxidizing power: Chlorine serves as a powerful oxidizing agent, helping to break down and remove organic matter, oils, and contaminants present in the water. This contributes to clearer and cleaner water.
  • Easy to use: Chlorine is relatively easy to use and maintain. Regular testing of chlorine and pH levels and occasional adjustments is a straightforward process for most, allowing for improved sanitation and water quality control.

Downsides of Chlorine

While chlorine is widely used, it has a few downsides.

  • Irritation and odor: Chlorine can cause skin and eye irritation, especially when chlorine levels are not properly balanced. Furthermore, the strong chlorine stink commonly associated with swimming pools can also be unpleasant for some individuals.
  • Chemical handling: Working with chlorine requires careful handling and storage due to its corrosive and potentially hazardous nature. Precautions must be taken to avoid accidents and ensure safe handling.
  • Chlorine byproducts: When chlorine reacts with organic matter, such as sweat or urine, it can form chloramines, which can lead to a variety of health issues in swimmers. 
  • Damage to swimwear and equipment: Chlorine can cause swimwear to fade and deteriorate and damage pool equipment and surfaces over time. Proper care and maintenance are necessary to minimize these effects of chlorine.

Which One Should You Use?

The choice between biguanide and chlorine as a pool sanitizer depends on various factors and personal preferences.

Biguanide might be a suitable option if:

  • You or your family members have sensitivities or allergies to chlorine.
  • You prefer non-chlorine sanitizing methods for personal or environmental reasons.
  • You want an odorless and more pleasant swimming experience.

Chlorine might be the better option if:

  • You’re on a tight budget.
  • You care about convenience and easier access.
  • You trust the timeless effectiveness of the product.

Ultimately, the decision should be based on your specific circumstances, including any sensitivities, preferences, budget, and availability of products.

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Frequently Asked Questions

Can you mix Baquacil with chlorine?

No, Baquacil and chlorine should not be mixed. Baquacil is a biguanide, while chlorine is a separate sanitizing agent. Mixing the two can cause unpleasant chemical reactions and should be absolutely avoided. It’s important to follow the instructions provided by the manufacturer of the pool sanitizing products you are using and avoid combining different sanitizer systems. 

Can you convert from a chlorine pool to biguanide?

Yes, you can convert from a chlorine pool to biguanide. To do so, first, check for metals in the water. If there are any, add Baquacil Metal Control. Then, make sure the free chlorine levels drop below 1 ppm. Next, add the Oxidizer to eliminate the remaining chlorine, and finally, the Sanitizer.

Can you convert a biguanide pool to chlorine?

Yes, converting a biguanide pool to a chlorine pool is possible. To do so, stop adding Baquacil (or other biguanide product), clean the filter, and adjust the pH and alkalinity to start. Then, shock the pool with a non-chlorine shock. Finally, add the chlorine slowly and get it to 1 ppm.

Bottom Line

And there you have it! As with any major purchase, before settling on a product, weigh factors such as cost, availability, sensitivities, and preferences when deciding between biguanide and chlorine. Remember, whether you choose biguanide or chlorine, in the end, what matters most is how you look after your pool to maintain that sparkling blue look.

Do you have more questions? Let me know.

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