- [Presenter] Is your pool water green?
Well, the good news is you don't have to drain your pool
and start over to get rid of it.
Here's a quick guide on how to kill pool algae fast
and keep it from coming back.
Let's dive in.
(upbeat music)
Real quick, before we continue,
if you want more help taking care of your pool,
be sure to grab our free pool care cheat sheet
at SwimUniversity.com/CheatSheet.
It's totally free and will help keep your pool clean
and clear all season long.
First, why do I have a green swimming pool?
Well, the culprit for green water is pool algae.
If it's light green, the algae is likely just starting
to take hold, but a deeper green
means you have a bigger algae bloom problem.
Green algae happens when your chlorine levels are too low.
When your chlorine levels are low,
your chlorine can't sanitize the water
and algae can start to develop.
Algae can also grow if your pool filter
hasn't been running properly
and the water hasn't been passing
through your filtration system.
If you've added chlorine and you're running your filter
and the algae just won't go away,
here's how to fix green pool water fast.
Make sure you follow every step in order to make sure
you're as efficient as possible.
One, brush the pool walls and floor.
Attach a pool brush to a telescopic pole
and scrub the pool walls, floor, steps, and any surface
the algae might be clinging to.
The goal is to get the algae floating in suspension
in your pool water, giving the chlorine a better chance
to kill it.
If you have a concrete pool,
it's best to use an algae brush.
Algae is tough and will stubbornly cling
to the pool surfaces, especially porous concrete
so a heavy duty brush works better than soft nylon bristles
in this case.
Two, test your alkalinity and pH.
Using test strips or a liquid test kit,
test the pH and alkalinity levels.
Your pH should be between 7.4 and 7.6.
It's okay if it's a bit lower
since you'll be adding shock later
that actually raises the pH.
Your total alkalinity should be between 100 and 150 parts
per million.
Again, it's okay if this is a bit lower.
If your pH and alkalinity are too high,
now's the time to adjust them.
Start with lowering your alkalinity first,
which should bring your pH down in range.
Then, retest your water.
And if needed, adjust your pH afterward.
Adjusting your pH and alkalinity at this stage
will ensure the shock treatment will be as effective
as possible.
Also, testing your water can happen before brushing.
It won't affect the algae killing process.
And if you need more help balancing your pH and alkalinity,
be sure to check out our other video
on pool water chemistry.
Three, shock your pool with chlorine to kill algae.
This is the most important step in clearing up a green pool
because shock is what kills the algae.
Pool shock contains a high level of chlorine
that will kill algae and sanitize your pool water.
For the best results, use a calcium hypochlorite shock
AKA cal-hypo shock that contains at least 70%
available chlorine.
If you usually use a non-chlorine shock,
you must use a chlorine shock to kill algae.
Non-chlorine shock just won't work
to get rid of algae spores.
And keep in mind, it's best to shock at night.
Otherwise, the sun can burn off the shock
and it will be less effective.
So how much shock do you need to kill the algae
in your pool?
It depends on the color of the algae.
A normal shock treatment is one pound of shock
per 10,000 gallons of pool water.
But that's if your pool isn't green.
If your pool is a light green,
you'll need to add double the shock to your pool water.
If your pool is dark green,
you'll need to add triple the amount.
And if your pool is black,
you'll need to quadruple shock your pool.
For example, if you have a 20,000 gallon pool
or about 7,500 liters and your water was dark green,
you'll need six bags of shock.
That's a triple dose.
If you need more help about how to add shock
to your pool water, be sure to check out our other video
or run your pool filter for eight hours and shock again
if needed.
As you let the shock work, run your filter system
for at least eight hours overnight.
But if you can run the filter 24 hours a day
until your pool is clear,
this will help clear your water faster.
If the pool is still green or teal in the morning,
hit it again with the same amount of shock
the following night.
And by the next morning, it should be cloudy blue.
In this case, cloudy water is actually a good thing.
If your pool is cloudy blue,
that means you've successfully killed all the algae
and it's floating in the water.
Keep your filter system running for at least 24 hours
to get the dead algae out of the water
and to ensure the shock has fully dissipated.
If you wanna speed up the process,
you can use a pool clarifier to help clear the water
more quickly.
Or if you want a more powerful treatment
to clear up the cloudy water, use a pool flocculant.
Keep in mind that you'll need to vacuum your pool
after using this.
And it only works if you have a filter with a waste setting.
Five, clean your filter.
Make sure you backwash your filter or change the cartridge
after all the algae is gone.
All that dead algae is caught in your filter medium
so now it's time to clean it.
If you need more help on when and how to backwash your sand
or DE filter, be sure to check out our other videos.
Number six, test your water again
and adjust your pool chemicals.
When your pool isn't green anymore or you have cloudy blue
or clear water, test your water again.
This time, test for pH, alkalinity, calcium hardness,
and your chlorine levels.
And add chemicals as needed to balance things out.
Once you made sure all your levels
are where they need to be,
you're ready to enjoy your pool again.
So now that your pool is clear,
how do you keep pool algae from coming back?
Well, the best way to keep algae away
is keeping your chlorine levels in the right range.
This means testing your water at least once a week
or more often if you're noticing fluctuations.
If you noticed your levels are a bit on the low side,
don't wait for things to get worse.
Add chlorine immediately.
And if you have a salt water pool,
make sure your salt water generator
is keeping your chlorine levels consistent.
If you wanna take more preventative measures,
you can also add algaecide
during your regular pool maintenance.
But your best bet is to just stay on top
of your chlorine levels.
If you need more help with pool maintenance,
grab our free pool care cheat sheet
at SwimUniversity.com/CheatSheet.
And if you found this video helpful,
leave a comment, hit the like button,
and subscribe for more pool maintenance tutorials
throughout the season.
That's it.
Thanks again and happy swimming.