algae cooling tower
June 26, 2018
By Reid Hutchison

How to Prevent Algae in Cooling Water Systems

algea cooling towerWith the summer heat already upon us, most facility managers are using their cooling towers daily. Cooling towers are a great way to keep your buildings comfortable, but they require maintenance: you’ll need to clean and disinfect them regularly to prevent algae and biofouling growth.

Algae growth spells trouble for cooling towers because it leads to Legionella growth. Legionella is the bacteria that causes Legionnaire’s disease, a dangerous and potentially fatal illness. But that’s not the only reason you should be focused on algae prevention. Algae growth can also hurt your cooling system’s efficiency, block screens and distribution decks, interfere with water flow, and drive up your cooling costs.

Why does algae grow in cooling towers?

Algae needs three things to grow: moisture, sunlight, and nutrients. Cooling towers are open to the outside air, so they often allow outside microbes (nutrients for algae) and sunlight into the water. As a result, algae can quickly grow out of control if left unchecked.


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How do I control algae in my cooling tower?

Algae in your cooling tower is best prevented by:

  • Cleaning your cooling towers regularly, according to your manufacturer directions.
  • Developing and following an effective water management plan, which will outline when your cooling tower may be in need of extra cleaning. Your plan may include checking the cooling tower regularly to look for signs of algae, biofilm, or sediment.
  • Using chemicals to prevent algae growth and/or kill existing algae. Some chemicals, such as chlorine, may be used in low amounts for extended periods as a preventive measure. Others, such as those that kill algae, may be used in short spurts or “shots” to eliminate any algae that has begun to form. Many different types of chemicals are available, and the ones you choose will depend upon water pH, their compatibility with one another, and your specific cooling tower.

There is no single solution for preventing algae in a cooling tower. Chances are, you’ll need a multi-faceted approach that focuses on being proactive in preventing algae, not just treating it once it’s there. That’s because even a small amount of algae can quickly grow out of control, setting you up for the health dangers and efficiency problems we mentioned above.

Ideally, you’ll use your water management team to create an algae prevention plan. If you don’t have your water management team established yet, start here. You’ll also need to detail your algae prevention strategy in your overall water management plan; learn how to create an effective water management plan here.

How do I save money on chemicals, but still keep algae in check?

Chemical treatments for cooling towers are necessary to prevent bacteria growth and costly repairs to your cooling system. But, that doesn’t mean you need the most expensive treatment out there. More money doesn’t always mean better algae control. In fact, you could end up spending money on chemicals you don’t even need. On the flipside, you don’t necessarily want to choose the very cheapest option either, especially if it’s not suitable for your cooling towers and type of water.

The best way to lower your chemical costs is to know the exact type of chemicals you need, when to use them, and how much to use. When you have this knowledge, you can be sure that you’re not only saving money by avoiding costs for unneeded chemicals, but that you’re using chemicals that will be the most effective and safe.

Choosing the right chemicals for your cooling tower

How do you know what your chemical “magic formula” is? Start with a laboratory analysis of your water. This analysis should be conducted by a water treatment expert and should include information about how your water system performs, areas you need to address, the type of algae you need to prevent, and other data that is specific to your facility.

After you have this analysis, your water treatment expert should outline your chemical needs and ideally, create a custom formula that will solve your issues and keep your water systems running exactly as designed. Then, you’ll be able to implement the right amount and kind of chemicals that will keep your cooling system safe and efficient without unnecessary expenses.

Keeping your cooling tower free from algae is an important job. Find out how HOH Water Technology can help you with this task and your other water management needs. Check out our capabilities and learn more about how our experts can do the legwork for you, saving you time, energy, and stress.

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