Green Pool

The Complete Guide to Controlling and Treating Green Algae in Your Swimming Pool

The single biggest problem that all swimming pool owners have to deal with is green algae in their pool. But if it is such a common problem, why hasn’t someone solved it with a permanent solution? To answer this, first we need to fully understand what algae is and why it grows in your swimming pool.

What is Algae?

Algae are single-celled marine plants. Algae are present in air, soil, water and our environment. In favorable conditions (which include water, warmth, sunlight and nutrients) algae growth is accelerated in swimming pool surfaces. It can float freely in the water or attach itself to the surface of the pool walls.

Algae is introduced to a swimming pool in various ways. Some sources of algae spores are wind and rain. Algae spores also can be carried into the pool from leaf debris or dirt, contaminated swimsuits or pool equipment from other swimming pools.

Once introduced to your swimming pool, poorly sanitized water will allow the algae to grow rapidly (this is called an algae bloom). Poor water circulation, inadequate pool filtration, unbalanced pool water, unstable pH and Total Alkalinity, compromised Chlorination and damaged and worn pool surfaces can lead to overgrown algae in the swimming pool.
One of the most common times to find an algae bloom is on opening the pool at the beginning of the season, since has not been circulated and filtered for a long time. Once algae spores get into the pool with the above conditions they can grow very quickly – often in just a few days.

Algae Varieties

Algae have several varieties, however there are three main varieties which are seen in swimming pools:

  1. Blue-Green Algae; most common and simplest form of algae.
  2. Yellow or Mustard Algae; which is the mutated Green algae. It grows in the shady side of the pool. Usually remain on the same side each time that overgrow and it is slightly harder to treat although is easy to sweep from the pool as it is present as powdery yellow dirt.
  3. Black Algae; which are the hardest to treat algae species because they actually attach itself to the wall and plaster of the pool like having a root and anchor and become part of the surface of the pool walls and floor. It does not respond to normal Chlorine shock and needs super-shock. Can survive in sunshine and shade.

There is another mutated form of algae which is pink algae, but it is rarely seen in swimming pools, they are only found in natural ponds and lakes.

Negative effects of Algae

Algae consume carbon dioxide, which lowers pH levels and makes maintaining water balance of the pool very difficult.

Algae also cause slippery pool walls which creates hazards and the potential for injuries in water.

Once algae are visible, a substantial problem exists. One of the major problems caused by algae is an overgrowth of bacteria in the water. Algae use carbon dioxide and sunlight, and give off oxygen like most other plants. Most bacteria found in swimming pools consume oxygen and give off carbon dioxide. Therefore bacteria and algae consume the by-products of the other, and flourish fast in pool water.

Algae also are harmful to the pool surface and plaster, causing the water to become cloudy. Algae overgrowth and dead algae in the water causes discoloration and damage to the pool surface. It can also clog filter elements, decreasing filtering efficiency.

Another problem with algae is that it consumes the chlorine that should be working on pathogens. In other words it increases the chlorine demand, and large spots of algae provide shelter for harmful bacteria (as explained above).

Blue-Green Algae

This algae species has its name by making the color of water look green (and occasionally blue/green).

Although the amount of the blue-green algae which grows in swimming pools are not harmful directly to humans, algae overgrowth causes bloom and scum.

The scum affects the quality of water and can carry toxins (produced either by specific species of algae or its harboring bacteria) that are harmful to human body and cause problems as subtle as skin irritation to serious respiratory problems.

Blue – Green algae (cyanobacteria) are the most common algae in swimming pools. Algae can stick to the pool walls, although it brushes off easily. Growth of green algae can be controlled in a pool by using the correct amount of chlorine and pool shock, keeping the water pH less than 7.6, providing good filtration and regular water circulation.

How to Treat Algae Overgrowth in Your Pool

It is much better to focus on prevention rather than treatment when it comes to algae. Many problems, time and money can be saved if an algae prevention program is in place. The plan should include routine brushing of pool surfaces to dislodge dirt that can accumulate in small spaces and keeping leaf debris out of filters, skimmer baskets and lint strainers. The areas where water flow is slow have to be well shocked and the water kept in good chemical balance.

If there is a chronic algae problem, or it is algae bloom due to closure of pool, it is important to not spread algae spores to other areas of the pools with brushes and infested vacuum hose. Use onsite equipment or disinfect equipment thoroughly. Again the secret is to maintain good chemistry at all times. You may need to add Phosphate measurement to your pool chemistry tests and measurement because high Phosphate can also leads to algae problems or be caused by algae overgrowth.

To remove algae, brush the walls well, make sure all equipment such as vacuum hose, filter pipe and brush are checked and cleaned from algae residuals and spores. This vigorous cleaning needs to be done before you add chemicals to the pool.

Run the pool system and filter 24/7 and shock the pool in the evening when the water is cooler, there are no swimmers and there is no sunlight to interfere with chlorine levels. Make sure you close the pool and turn off the pump. The treatment of choice is to shock the pool at 30 ppm.

To shocking the pool and get chlorine levels of 30 ppm, Trichlor Granules which have 90% available chlorine should be used. For every 10,000 gallons of water, 2.8 lbs of granules are needed (for a 20,000 gallon pool use 5.56 lbs of Trichlor granules).

Treating Blue-Green Algae

  1. Make sure you have enough time for the procedures and cleaning process. Algae can grow very fast and if all the steps are not completed timely (leaving it for couple of days without testing and checking water) algae residuals will grow fast to the original levels and the entire effort will be wasted.
  2. Run the filter and the pool system for 24 hours. It is important to run your pool system 24/7 during this procedure.
  3. Sweep, clean and vacuum the pool twice daily. Make sure algae is not collected in the skimmer basket, filter, vacuum hose or your pool equipment.
  4. Sanitize Vacuum hose, filter openings and skimmer basket by using liquid chlorine.
  5. Use waste valve on the filter for clearing the pool and use backwash on a sand filter daily (you may want to add DE [Diatomaceous Earth] powder to your sand filter).
  6. Check and adjust the pool water pH and water balance daily (keep the pH level at 7.2-7.4). I recommend at the early stages of this procedure keep the pool water pH near 7 and later as the algae is cleared and pool water is sanitized, raise pH to 7.2-7.4.
  7. Check filtration and circulation (water flow), filter pressure and backwash daily.
  8. Super shock the pool to free chlorine levels of 30ppm (this should be checked and treated to 30 PPM every 24-48 hours) until the water is clean and water balance reading and chlorine demand and calcium hardness are balanced. (Use liquid chlorine or Di-Chlor or Tri-Chlor at this stage).
  9. After 48 hours measure free chlorine. Bring the free chlorine level to the shock level (free chlorine 10ppm and combined chlorine less or equal to 2 ppm). Leave the pool for half an hour and test the free chlorine. If the chlorine falls below shock level after half an hour shock the pool again. Repeat this step till the chlorine level does not fall after half an hour and the water free chlorine remains in the shock level for at least one hour.
  10. For a faster process use of a good Floc can help to speed up cleaning the dead algae. (Flocculation is a coagulation of algae dead bodies in the water and making a “floc” – mass or volume of collection of algae bodies- that are easy to remove from water).
  11. Lower phosphate level of the pool water.
  12. Backwash your sand filter after completion and acid wash cartilage filters.

If you have chronic algae problems, consider using algaecides and get professional a assessment instead of doing it yourself.


There are a number of algaecides on the market that can help reduce algae growth. The most cost effective and reliable way to treat green algae is by having free active chlorine. Some alternatives include quaternary ammonium, or QUATS, which is inexpensive; unfortunately these products tend to produce foam.
Other products such as cationic polymers or Poly Quats are also effective and don’t foam, but are expensive.


Remember that algae prevention is much easier than treatment, so keep your water balanced and shock your pool every few weeks in the summer time to make sure you don’t get an algae bloom.

How to Vacuum a Swimming Pool

How to Vacuum a Swimming Pool

There’s a dead cockroach at the bottom of the pool. I’m not going swimming!

There is nothing more disgusting than looking into a dirty pool and seeing dirt or dead insects at the bottom. So it makes sense that keeping the pool clean is an important factor in enjoying swimming and playing in the pool. Beyond that, a clean pool is also important to keep the water balanced. Dirt and contamination affects the pool water’s balance and chemical properties, as well as having a negative impact on our skin and body.

One of the most important aspects of keeping pool clean, is vacuuming the pool.

I recommend that you vacuum your pool at least once a month, as well as after each pool party, at the beginning of the swim season when you open the pool, and also when you are preparing to close the pool for winter.

Cleaning and Vacuuming Swimming Pools

Prior to vacuuming a pool you need to clean up large objects such as small branches in the water (or at the bottom of the pool). The filter can become clogged up, requiring frequent backwashing if larger objects are vacuumed (instead of being removed using a leaf skimmer).

Cleaning leaves and objects from a pool

Step One: Removing Leaves or Larger Objects

    • Although a leaf rake is useful for collecting leaves floating on the surface of the pool water, I prefer to use a leaf skimmer. It is much easier to unload collected leaves from a leaf skimmer.Leaf Skimmer / Leaf Rake
    • Using the leaf skimmer, collect surface debris and floating leaves with a swiping motion of the skimmer on the surface of the water.


  • Use a scooping motion to collect any objects, leaves or branches from the bottom of the pool.


      Place the leaf simmer on the bottom of the pool a few inches (at least 4-5 inches) away from the object. Use a fast forward push, then a scoping motion to collect the debris.

The fast movement forward pushes the water helping to float the object off the bottom of the pool slightly, and the scooping motion is used to catch the object in the leaf skimmer.

    As you pull the skimmer out the water, gravity will keep the object on the leaf skimmer.

  • Clear all the large objects and dirt from the bottom of the pool and the surface of the water.

Step two: Cleaning the Steps and Walls

  • Clean the steps and walls by brushing them. These need to be brushed manually because most automated / robotic pool vacuums cannot reach these areas.
  • Brushing of the walls and steps need to be done at pool opening and closing, and also at least once a week during swim season.
  • It is important brush twice a day in a newly resurfaced or newly built swimming pool. In a resurfaced or a newly built pool be sure to use a new brush so the plaster is not damaged.

Brushing a Pool

Effective Brushing:
  • Clean the steps and walls of the swimming pool with a pool brush.
  • Clean the steps using a swiping motion and brush the debris to the deep end of the pool water. Do not use very fast rotating movement or splashing movement as the debris will be disturbed, floating up and mixing with pool water. Use a gentle and soft swiping motion to move debris and dirt forward toward the deep end of the pool.
  • Brush the walls from upper parts just below the water surface downward toward the bottom of the pool. This will break away any algae, calcium deposits on the wall or any other wall surface debris. Use a gentle and soft swiping motion on the walls and then push the debris toward the deep part of the pool water.
  • If there are any visible large objects or debris collect them using the leaf skimmer prior to vacuuming.

Step three: Vacuuming

The equipment needed for vacuuming is:

  1. Pool vacuum cleaner head
  2. Long vacuum cleaning hose (the minimum length of the hose is at least the length from the shallow end of the swimming pool to the deep end of the pool – I recommend + 1 yard. The longer the hose, the easier the procedure will be (as long as the hose does not get tangled or bent).
  3. Adjustable pole at least 8-14 ft.

Setting up the vacuum:

  1. Attach the vacuum head to the pole.
  2. Hook up the hose to the top hole of the vacuum head.
  3. Place the vacuum head in the water and guide it to the bottom of the pool by holding the pole firmly.
  4. Secured the pole to the side of the swimming pool so it does not fall into the water.
  5. Start to feed the attached hose gradually with you hand under the water. This should start from the point nearest to the skimmer or at the opening of the skimmer into the pool. As you feed the hose under water the air bobbles are released from the head of the vacuum under water and also air will release from the opening of the hose. Feed the entire hose under water.
  6. When all the air is released, keep the open end of the hose under the water and feed it under the water from the skimmer outlet to the skimmer and attach the hose to the skimmer.
  7. Hopefully you have cleared the large dirt from the pool prior this point but if there are still visible dirt or very cloudy water use the “Waste” valve on your filter to prevent clogging up the filter.
  8. If the pressure decreases or vacuuming and filtering stops, there may be two reasons:
    1. It may have air in the system – the continued running of the pool pump will get the air out shortly.
    2. There has been too much dirt and debris. Backwash or clean the pool filter.
  9. Vacuum the pool with a swiping motion of gentle and soft back and forward motions. Make sure you do not swipe too fast or rotating motions so you don’t disturb the dirt in the water.
  10. After finishing all the walls, corners and the bottom of the pool. Turn off the pool pump.
  11. Take the pole and bring the vacuum head close to you. Gradually pull the hose out of the water and allow the water in the hose to drain from the head of the vacuum. Then take the vacuum head and the pole out of the water.
  12. Detach the hose from the vacuum head and allow the residual water to pour out. Now detach the pole from the vacuum head.
  13. Make sure you clean the skimmer basket in the waste bin.

Now you can bask in the glory of a beautifully clean pool. Or just splish splash 🙂

How to shock a pool

How to Shock a Swimming Pool – The Ultimate Guide

Shocking a swimming pool does not involve lightning (despite what it sounds like).

Shocking a pool actually means hyper-chlorinating the pool water for sanitation purposes i.e. to kill all the algae and bacteria.

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How To Change Sand In a Swimming Pool Sand Filter

How To Change Sand In a Swimming Pool Sand Filter

Sand filters are known to be the lowest maintenance of the three types of pool filters.

The length of time the sand lasts before it needs to be changed depends on the filter structure, the size of the filter and the amount of the water that goes through the filter.
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Clean Cartridge Filter

How to Clean Swimming Pool Cartridge Filters

Human beings are not fish.

Yet we seem to love being in the water. Especially if the water is not salty and is in our backyard – as in a swimming pool.

But swimming in a pool can be a hazard to our health if the water is not clean.

The water in a swimming pool is cleaned by a filtration system. All swimming pools have a filtering system to keep the pool fresh and usable. The most popular type of filter used is a cartridge filter.

Today I’m going to give you exact instructions on how to clean swimming pool cartridge filters.

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Adjusting the pH level of pool water

Pool Water Balancing – Adjusting the pH Level of Pool Water

“My eyes are burning!”

That’s what my daughter said to me as she climbed out of the swimming pool.

“I don’t want to swim anymore.”

I’ll never forget that day. I looked at the pool water and it looked a little green. I instantly knew I had to check the acidity and pH level of the water.

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Water Circulation Saves Money

How Water Circulation in Your Pool Will Save You Money

What does coffee in a cup have in common with water circulation in your swimming pool? I’m about to tell you, but before that, let me ask you…

What is the fastest way to cool down a hot cup of coffee?

Drop an ice cube in it! Of course. But that would be cheating.

Most people don’t know this, but the fastest way to cool down your hot coffee is by not stirring it.


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How to Make Your Pool into a Reflecting Pool

The reflecting pool, the ultimate symbol of wealth and serenity. What better way to accentuate the best aspects of your home than with a reflecting pool giant mirror?

Well, you don’t have to have a million of dollars to build a reflecting pool or pond.

You can turn your standard pool into a reflecting pool quite easily, but before I show you how, let me tell you a story about Benjamin Franklin.

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