Everything You Need to Know About Algae

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Everything You Need to Know About Algae

Prevention, Removal, and Potential Health Risks

algae poolIf you own a pool, you’ve likely seen it turn green. It may even happen every year, season, month, or week depending on how you take care of it. Swimming pools require a lot of maintenance, which a lot of owners think is optional. Although it is optional, it will require a lot more work to make it useable again if you don’t take good care of it in the first place. In some cases, it can result in costly repairs. Algae, for example, can build up on your pool and result in some potential health risks.

What are Algae? Are They Dangerous?

green algae Algae are tiny organisms that build up and multiply on your liner. The algae themselves are not harmful to humans, although they are nasty and slimy. The problem results from when they produce waste products. The waste they produce attracts other bacteria which are dangerous to your health. Swimming in this bacteria-infested water is a great way to catch infections and diseases. Not to mention algae give your water a nasty, green tint. In severe cases, the water is so green that you cannot see more than an inch or 2 under the surface!

Where Does Algae Come From? Everywhere

lake with algae Put simply, algae are always around. In fact, it builds up all over the place. Find a bucket that has been lying around outside for a few days after a rain and you’ll likely find algae growing inside. They love water and sunlight, and what better way to get this combination than in your beautiful, clean, unoccupied swimming pool? The major issue is they duplicate themselves to become a larger problem over time. Algae cannot survive in certain pH levels, which is why it’s important to keep your pool’s pH levels as steady as possible. Anyone with a pool knows that after a heavy rainstorm, your pool’s pH balance is completely thrown off balance. The most common causes of algae are:
  1. Heavy rains – instantly raises your pool’s pH
  2. Poor pool chemical management (often in combination with heavy rains)
  3. Poor pool management (lack of cleaning)
  4. Broken filter/pump
  5. Unused pool
You absolutely must keep your pool cleaned and the chemicals balanced. If you go away for a weekend or longer, shock your pool before you go to help prevent algae from building up while you’re gone. It’s also a good idea to keep a cover on it while you’re gone, even if it’s not a complete closing of the pool. You just need something to keep the rainwater and large debris from entering the pool. The filter should handle the rest.

Algae Prevention in Pools: Keeping Your Pool Blue!

blue pool water There are 2 core elements you need to keep in mind about algae:
  1. They will not accumulate in the standard pool pH levels of 7.2-7.6.
  2. They cannot and will not accumulate in moving water (this is why they are often found under rocks in rivers, not on top).
CHEMICAL BALANCE: As you’ve heard many times in the past, you absolutely must keep the chemical levels balanced. Take a look at your testing kit and follow its instructions carefully. In the case of algae, your pH level is the number one concern. Other issues can arise with total alkalinity, calcium hardness, and chlorine levels being out of whack. CLEANING: On top of maintaining chemical balance, your pool absolutely must be kept clean. If algae begin to build up, you’ll want to scrub and vacuum the pool thoroughly to keep it from growing further. Regular cleaning can be a hassle and we completely understand (and agree), which is why there are now automatic pool cleaners available. Although they cost a few hundred dollars, these robotic cleaners will glide around the floor and up the walls all while cleaning and filtering your pool. SWIMMING: One great and easy way to keep the water moving is to simply use the pool. Get out there and jump in! Just swimming along will move the water significantly, meaning algae cannot build up. Algae have to be still on a surface for many hours in optimal conditions for them to grow. They aren’t strong enough to simply grab on and hold on, so moving water means they are thrown into the filter and sucked out of the water. ALGAECIDES: Algaecides are products available to eliminate and prevent algae entirely. Combined with general pool maintenance (cleaning and chemical balancing), we’ve never seen a case where algae continued to grow. They are not as resilient as people claim; however, they will consistently return if you do not keep the pool maintained. A popular choice among most pool owners is Algae Defense. FILTER & PUMP FUNCTIONING: As long as the pool’s pump is functioning, the water will be constantly moving. On top of this, the filter will pull out any unwanted materials in your water it finds, including algae. This is why you rarely find algae buildup on the side of the pool when the pump is running, except in extreme cases. Ensure your pump is functioning properly and if it’s not, call a pool repair company.

Algae Removal: Killing the Green Monsters

clean swimming pool

If you have an algae problem and your pool is turning green (or is already completely green), then follow these steps to kill the green monsters:
  1. Test your chemical balance and adjust it accordingly. – If your water is turning green already, you may want a higher pH level – as high as 8.0 would work well.
  2. Clean thoroughly. – You’ll have to brush the whole pool. Do not get in the pool to clean it. You can use long-arm brushes to scrub the pool down. Automatic pool cleaners will not cut it at this stage. They will be used later on down the road.
  3. Shock it. – Don’t hold back either. Most of the time, you’re shocking it to just get rid of what you can’t see. In this case, you’re shocking what you can see. Follow the directions on the bucket the shock came in, but add the shock until the water becomes cloudy and you no longer see green.
  4. (optional) Add Algaecide. – If you have an algaecide product, this is where you’ll add it. If the case is not extreme, it’s often unnecessary.
  5. Clean again. – After all is said and done, it’s not. Now you should hop in (once the chemicals are down to normal levels again) and vacuum/brush some more. If you have an automatic cleaner, go ahead and run that instead or in addition to your cleaning.
  6. Clean your filter. – Your filter has circulated tons of algae through the system and you’ll want to get it out of there. Pull out the filter and hose it out with a light stream. Use just enough pressure to get the filth out of it, but do not use a pressure that would damage the fine threads.


Algae can be nasty and will turn your pool green and unhealthy if left untreated. The best defense against algae is a good prevention system. Keeping your chemicals balanced, pool cleaned, and a functioning filter will ensure the algae stays out. Also, be sure to keep the water moving by using the pool and leaving the pump running. If your pool has turned green and you do not have the time to remove the algae yourself, it’s always a good idea to hire a pool expert. We can come out, clean the pool, and provide tips and systems to ensure the algae stays out. Contact us for more information or if you have any questions.

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