How to Get Rid of Blackspot Algae in Your Swimming Pool
Understand black algae., Test pool levels and balance chemicals often., Shock the pool regularly., Circulate the water., Clean your filter., Consider using a preventative algaecide., Brush and vacuum your pool on a weekly basis., Brush the pool...
Step-by-Step Guide
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Step 1: Understand black algae.
Like any alga species, black algae (which are really blue-green algae that look black) will grow quickly in warm water on a sunny day.
Black algae are chlorine-resistant, because they have a protective outer layer that makes regular sanitization ineffective.
While algae aren’t harmful, their presence can be a sign that other bacteria are present.Other alga species that are common in pools are green algae, mustard or yellow algae, and pink algae, which is actually a bacterium.
Algae tend to bloom in pools that have poor circulation, poor filtration, a high pH level, and a low chlorine level. -
Step 2: Test pool levels and balance chemicals often.
Chlorine should be somewhere between
1.0 and
3.0 parts per million.
The pH level should be between
7.2 and
7.8.
Alkalinity should be between 80 and 120 parts per million.
Test these three levels once or twice a week and correct as needed.Calcium hardness should be tested monthly, and the ideal level is between 180 and 220 parts per million. , On a weekly or bi-weekly basis, shock your pool to remove chloramines (chlorine molecules that have attached to other particles) and raise chlorine levels quickly.
There are four products you can use to shock your pool, and they are:
Calcium or lithium hypochlorite Granular chlorine Potassium peroxymonosulfate , Keeping the water in your pool moving is one of the best preventative measures for algae.
Not only will it make it harder for alga spores to take hold, it will also ensure that sanitizing chemicals are evenly distributed.
Monitor and clean the skimmer and strainer basket regularly., A clogged filter won’t work as well, and it will slow down the flow of water.
In warmer months like July and August when algae have the best chance of blooming, run the pump for about eight hours over the course of the day., Especially if you’ve had trouble with algae in the past, consider adding algaecide to your pool on a monthly basis.Ammonia-based algaecides should work for green algae, but metal-based (specifically copper) algaecides are necessary for black algae., Brushing will remove dirt and spores, and prevent algae from taking hold.Brush the walls, floor, and steps of the pool.
Once you’ve completed your brushing, vacuum the pool to dislodge and remove any spores that have settled on the bottom.
Use a steel brush for concrete or plaster pools.
Use a nylon brush for vinyl, fiberglass, acrylic, or painted pools., Brush daily for a week with the proper brush for your pool, paying special attention to algae-affected areas.
The protective layer that forms on black algae makes the algae otherwise impervious to regular sanitizers, so you must brush the algae to break through this layer so that chlorine and algaecides can kill the organism.Black algae have deep roots that work their way into the walls, grout, and filters in your pool.
If the roots aren’t destroyed, the organism will continue to grow back.
Try rubbing the algae spots with a chlorine tablet after brushing. , After brushing the pool for the first time, add a copper-based algaecide that has an active ingredient concentration of at least 30 percent.Aim the water return jets at the affected areas., After the algaecide has run its course, shock the pool.
Continue your daily brushing, and after three days, shock the pool again., This will remove the dead algae and any debris that has settled on the bottom of the pool.
To remove larger quantities of deal algae, consider adding an alum flocculant, which will cause the material to clump together for easier removal., Black algae can not only clog the filtration system and make it less efficient, but spores can also hide in the filters and bloom again when you least expect it.
Wash all bathing suits and towels in the washing machine, and dry them in the dryer to kill any algae that may have attached to the fabric.
Sanitize pool equipment and toys by scrubbing them with a bleach-based cleanser., You should do this regularly, but especially if you have recently adjusted the chemical levels of the pool. -
Step 3: Shock the pool regularly.
-
Step 4: Circulate the water.
-
Step 5: Clean your filter.
-
Step 6: Consider using a preventative algaecide.
-
Step 7: Brush and vacuum your pool on a weekly basis.
-
Step 8: Brush the pool.
-
Step 9: Add algaecide to the water.
-
Step 10: Shock the pool.
-
Step 11: Vacuum the pool.
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Step 12: Clean and sanitize filters
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Step 13: equipment
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Step 14: and toys.
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Step 15: Test the water.
Detailed Guide
Like any alga species, black algae (which are really blue-green algae that look black) will grow quickly in warm water on a sunny day.
Black algae are chlorine-resistant, because they have a protective outer layer that makes regular sanitization ineffective.
While algae aren’t harmful, their presence can be a sign that other bacteria are present.Other alga species that are common in pools are green algae, mustard or yellow algae, and pink algae, which is actually a bacterium.
Algae tend to bloom in pools that have poor circulation, poor filtration, a high pH level, and a low chlorine level.
Chlorine should be somewhere between
1.0 and
3.0 parts per million.
The pH level should be between
7.2 and
7.8.
Alkalinity should be between 80 and 120 parts per million.
Test these three levels once or twice a week and correct as needed.Calcium hardness should be tested monthly, and the ideal level is between 180 and 220 parts per million. , On a weekly or bi-weekly basis, shock your pool to remove chloramines (chlorine molecules that have attached to other particles) and raise chlorine levels quickly.
There are four products you can use to shock your pool, and they are:
Calcium or lithium hypochlorite Granular chlorine Potassium peroxymonosulfate , Keeping the water in your pool moving is one of the best preventative measures for algae.
Not only will it make it harder for alga spores to take hold, it will also ensure that sanitizing chemicals are evenly distributed.
Monitor and clean the skimmer and strainer basket regularly., A clogged filter won’t work as well, and it will slow down the flow of water.
In warmer months like July and August when algae have the best chance of blooming, run the pump for about eight hours over the course of the day., Especially if you’ve had trouble with algae in the past, consider adding algaecide to your pool on a monthly basis.Ammonia-based algaecides should work for green algae, but metal-based (specifically copper) algaecides are necessary for black algae., Brushing will remove dirt and spores, and prevent algae from taking hold.Brush the walls, floor, and steps of the pool.
Once you’ve completed your brushing, vacuum the pool to dislodge and remove any spores that have settled on the bottom.
Use a steel brush for concrete or plaster pools.
Use a nylon brush for vinyl, fiberglass, acrylic, or painted pools., Brush daily for a week with the proper brush for your pool, paying special attention to algae-affected areas.
The protective layer that forms on black algae makes the algae otherwise impervious to regular sanitizers, so you must brush the algae to break through this layer so that chlorine and algaecides can kill the organism.Black algae have deep roots that work their way into the walls, grout, and filters in your pool.
If the roots aren’t destroyed, the organism will continue to grow back.
Try rubbing the algae spots with a chlorine tablet after brushing. , After brushing the pool for the first time, add a copper-based algaecide that has an active ingredient concentration of at least 30 percent.Aim the water return jets at the affected areas., After the algaecide has run its course, shock the pool.
Continue your daily brushing, and after three days, shock the pool again., This will remove the dead algae and any debris that has settled on the bottom of the pool.
To remove larger quantities of deal algae, consider adding an alum flocculant, which will cause the material to clump together for easier removal., Black algae can not only clog the filtration system and make it less efficient, but spores can also hide in the filters and bloom again when you least expect it.
Wash all bathing suits and towels in the washing machine, and dry them in the dryer to kill any algae that may have attached to the fabric.
Sanitize pool equipment and toys by scrubbing them with a bleach-based cleanser., You should do this regularly, but especially if you have recently adjusted the chemical levels of the pool.
About the Author
Scott Perry
A seasoned expert in education and learning, Scott Perry combines 12 years of experience with a passion for teaching. Scott's guides are known for their clarity and practical value.
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