How to Get Rid of Algae In Your Pool [The ULTIMATE Guide]

How to get rid of algae in pool?

So you have algae in your pool, the water looks slimy and nobody wants to swim? Although you’ve heard of the proverb “Prevention is better than cure” you realize that with algae infesting your beautiful pool you need a cure now.

That’s OK, it happens to us all but in the future, do try to prevent these unwelcomed single-celled plant forms from appearing in the first place. You will save yourself the time and hassle of getting rid of algae in pool later. Getting rid of algae in pool takes some time and effort but we’ll help you with useful advice on how to get algae out of a pool.

Algae exist in a wide variety of colors but the next few are the most common in pools.

Green Algae

The most common form of algae in pools, green algae, vary in color from blue-green to yellow-green to dark-green. Green algae in pool can be free floating or wall-clinging.

Black Algae

Black Algae form in crevices and cracks of your pool surfaces. Black algae are often found in concrete or plaster finished pools where they plant roots. No brushing - no successful treatment if you want to kill algae in pool.

Mustard (yellow) Algae

Mustard or yellow algae are chlorine-resistant forms of green algae. They look like dirt but they are much worse than that.

So, if you want to find out how to get algae out of pool you need to know what type of algae you need to deal with and what kills algae. Now, on to the task at hand: pool algae removal.

How to get rid of algae in a pool?

First off, you need to remove all leaves and debris as it is almost impossible to restore clear water to a pool which is very dirty with debris. Algae feed on almost anything and your filter will not work efficiently.

After removing debris, check that your top filter system is clean. If not, clean it thoroughly. Adjust valves for optimum circulation and let the pump run 24 hours a day until the pool clears.

Turn on automatic cleaners as they will help stirring and speeding things up. Backwash if necessary, but only if pressure rises by at least 5 psi, or if you find the flow rate significantly diminished.

How to kill algae in pool with suspended green algae?

You need to shock the pool. Put in as much hypochlorite as it takes to turn the pool a cloudy, bluish-gray color. This will usually require about 30 ppm of free chlorine.

The higher your cyanuric acid level is, the more pool shock will be required. A good amount would be between 2 to 5 lbs of granular pool shock per 10,000 gallons of pool water. If cyanuric acid levels are above 30 ppm, or if the algae bloom is especially aggressive you will have to use more.

Chlorine is your best weapon against algae. To be specific, you will need to use calcium hypochlorite pool shock to super-chlorinate your water.

First, you need to determine how much algae is in your pool. If your pool looks very light green or you see very little yellow or black algae, you will need to double shock your pool by using 2 pounds of shock for every 10,000 gallons of water your pool holds.

If you pool is dark green or you see larger spots of yellow or black algae, you will need to triple shock your pool. Use 3 pounds for every 10,000 gallons of water.

Lastly, if your pool is black or really infested with yellow or black algae, you’ll need to quadruple shock your pool using 4 pounds for every 10,000 gallons.

Test the water the following day for pH and chlorine. You need to have your pool water balanced, paying special attention to pH level. If the chlorine level is still off the charts, you’re doing well. If it drops to a low level in 24 hours, you will need to shock the pool again, using even more hypochlorite the second time.

You will need to brush the walls and floors towards the main drain and vacuum the pool if necessary. Using a flocculent (chemical that allows all the particles in your pool to settle to the bottom so you can vacuum them out) may be a good choice after shocking, if the pool is still really swampy.

After the chlorine level has come down below 5 ppm, add the best algaecide for pools in your stock and brush the pool again. When it all settles, vacuum the pool to waste. Once the water clears, check and re-balance the pool. Clarifiers can be used to assist a struggling pool filter. Remember to run the filter 24/7 as long as it takes for the water to clear.

How to remove algae from pool if algae are clinging to the walls?

You can follow the same advice: first shock, then brushing, then use algaecide for pools, brush again, vacuum to waste or vacuum and then backwash the filter. Using a steel bristled brush is recommended for algae on plaster pools and nylon brush on vinyl. Filter plays important role in cleaning algae from pool so make sure to clean it in the meantime.

algae on pool walls

For black pool algae removal, the brushing part is very important. You need to tear through their protective layers so the chemicals can kill algae in pool from the inside out. You need to vacuum the dead algae later and backwash them out of the filter.

Trichlor is very effective when sprinkled on black algae spots. If they're on the wall rubbing the spots on the walls with a trichlor tablet or stick can also be effective to knock off the algae heads and get chlorine directly on the plant.

Follow up with a dose of copper algaecide, or high strength polymers.

Does algae appear season after season?

If swimming pool algae have been a problem in your pool for several years, you should drain the pool. A few years of algae builds up, dead algae and lots of other solids in the water will contribute to algae staying for a long time. You need to acid wash or pressure-wash the pool to kill the roots of all the algae in the plaster.

For pools with repeated algae blooms, you should check the level of phosphates in the pool. Also, look for sources of possible contamination from fertilizers or from soils washing in the pool during heavy rain.

For pool algae prevention, we need a combination of good filtration, sanitation and circulation. It may be time to consider changing the old filter. It's cheaper and easier to pay a little up front for more chemicals, electricity or better equipment than all the money and aggravation spent on fighting algae blooms.

Some more general advice on cleaning algae from pool

Remove all floats from the pool as well as all cleaning equipment and accessories, and sanitize them. Use chlorine or bleach solution. Make sure you thoroughly wash and dry all bathing suits.

Get your water tested to make sure you have the proper pH and alkalinity levels, and that your pool can hold chlorine successfully. You can use digital pool water testers or these great testing kits for dependable measurements.

It’s always best to wait until the late afternoon or dusk to brush the entire pool. Pay special attention to hard-to-reach places like under the pool ladders.

Turn on your filter and keep the pump running 24/7.

Shock your pool with the correct amount of shock as stated above. Make sure you cover the entire pool with shock as well as you can.

Let your pool run overnight. Sunlight can eat up 1ppm of free chlorine every hour. Shocking at night will allow the shock to do a more efficient job cleaning algae from pool.

Brush your pool for the next couple of days and brush it as often as you can. Make sure you keep a good level of pH, alkalinity, and chlorine during the fight. You can add a little clarifier to help speed up the process of getting your water crystal clear. Backwash your filter very thoroughly whenever pressure rises.

After a couple of days, if the algae are gone and the water is clear, you probably did a good job. Getting rid of algae in pool can easily be prevented with regular water checks and treatments so you don’t get in the situation to look for algaecide for pools to fight the battle for you as best algae killer for pools.

Make sure you keep your water chemistry under control and shock your pool once a week or two with 1 pound per 10,000 gallons of water and if you are persistent in taking care of your pool, you won’t have a problem with algae.

Enjoy the summer and keep reading! We’re here to help!

Laurie S.

As a multi home owner for 15 years I've tried out a ton of pool products and methods and have found out the best ones that work for me. I love helping out other people with real, honest advice and spending time with my family. If you have any questions please don't hesitate to contact me in the about or through a comment.

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