You are about to fight a war against pool algae. Many people have battled algae with great success, while others have failed. I have battled algae many times. I’ve helped thousands of pool owners around the world do the same. This guide is a proven formula for defeating algae every time and protecting your pool water from further infestations.
Are you ready for war?
Table of Contents
Chlorine kills algae. It works. You need to arm yourself liquid or granular chlorine before going into battle. I recommend using granular calcium hypochlorite chlorine shock sold in 1 lb. bags. “Shocking” is the term we use to super chlorinate a pool. That’s exactly how you’re going to kill the algae. Shocking for everyday maintenance is one pound of calcium hypochlorite granular chlorine per 10,000 gallons of water. You need a lot more than that to fight. Arm yourself to the teeth.
Know Thy Enemy
There are 3 stages of an algae infestation.
Teal green is the weakest. You will only need a low amount of chlorine to defeat it. Also, consider patches of algae growing on your walls to be teal green. Fight with a Double Shock: 2 lbs. per10,000 gallons
Green is the most common. It’s a bright green color. Fight with a Triple Shock: 3 lbs per 10,000 gallons
Black is the hardest to get rid of. We’re not talking about black algae, we’re talking about having so much algae in your pool that your water looks black. This will require everything you’ve got and will take the longest. Quadruple shock: 4 lbs. per 10,000 gallons.
Prepare For Battle
Run the pump and filter 24/7. Make sure the pH is between 7.4 and 7.8 and alkalinity is between 100ppm and 150ppm. Brush the pool before you attack to pull the enemy out of hiding on your walls, behind ladders and on stairs. Do not add any other chemicals until the algae has been defeated.
Sneak attack by shocking the pool at night — they’ll never see it coming. Hit it the first night with everything you’ve got. Dissolve each bag of shock in a bucket of pool water. Use a wooden paint stirrer to mix. Be very careful when working with granular chlorine. Wear gloves, eyewear, and old clothes you don’t mind getting bleached.
While the filter is running, pour the mixed bucket of liquid chlorine shock around the perimeter of the pool, making sure you get an even distribution. Once you’ve finished adding all the shock needed, keep the filter running and wait till morning.
Hopefully you will be success on your first attack, but if your pool water is still green, even a light green, you will need to repeat the shocking process again the following night.
Prepare for battle and deliver another attack at night.
Two attacks will usually do the trick if you’ve followed the battle plan correctly. In the case of a third attack, make sure you test your pool water before hand to confirm everything is still at the proper levels.
Your pool should be a cloudy blue at this stage. That means you’ve successfully killed all the algae, but your job is not quite finished.
1. Add the clarifier, according to directions for treatment and dosage
2. Resist the urge to backwash until the pressure rises 10 lbs over the normal running pressure. Sand filters will filter more effectively when they are somewhat dirty.
3. You can keep the chlorinator off for now, but check your chlorine carefully every day (pH and Alkalinity too), so it never drops below 1 ppm. When the chlorine level drops back down to 2-3 ppm, turn the chlorinator back on.
4. Keep running the filter 24 hours per day until it fully clears up, then cut it back to 15 hours per day.
Don’t let algae back on your turf. Chlorine will not only kill algae, but it will keep it away. Chlorine is most effective when the pH and alkalinity are at the proper levels.
1. Test your pool water twice a week.
2. Keep your pH reading between 7.4 and 7.6
3. Keep your alkalinity reading between 100 and 150 ppm
4. Keep your chlorine reading between 1 and 3 ppm
5. You can add algaecide or phosphate removers as a weekly backup (optional)