If you have a light green pool, you need to shock your pool in order to kill algae. Algae feeds off high pH levels and chlorine isn't as effective when your pH is high. You will need to lower your pH using hydrochloric acid.
Poor filtration or circulation – Water that is moving and being cleaned of particulate debris is much less likely to produce algae. Poor filtration and little to no water movement are two of the biggest causes for algae growth even in chemically maintained pools.
Just like how bacteria can resist antibiotics, algae can also become resistant to chlorine when they keep getting exposed to it and they aren't removed completely.
The only thing that kills algae is CHLORINE (or your sanitizing product, or one of the copper-based algaecides on the market). You need to raise the level of your chlorine – shock the pool – and maintain that high level until all the algae is dead. This may take 3 to 4 days. RUN THE FILTER 24 HOURS A DAY.
If your pool is green and cloudy, it's likely an algae problem. Algae can persist in a pool even after shocking. A green pool – especially one that turned green overnight or after rain, can also be from a pool pump that isn't properly circulating water or an issue with your filtering system.
Eliminating an Algae Bloom
To eliminate a green algae bloom, the recommendation is to breakpoint chlorinate to 30 ppm. Adding less than the breakpoint dosage can create more combined chlorine, exacerbating the problem.
Pool chemicals could be out of balance or the pH might be off. Chlorine levels and the right pH are key to keeping a pool clear. If a pool's pump or the filter isn't working right, the water may look murkier than usual. Storms or increased rainfall can affect your pool.
Use a pool brush to vigorously scrub any pool surfaces covered in algae, including the walls, floors and steps. Apply a green algaecide according to the directions on the label. Let the water circulate for 24 hours, then brush the pool surfaces again. Vacuum or backwash to remove any remaining dead algae.
So, this one is kind of obvious, but chlorinated water does not grow algae. If you always keep your chlorine levels consistently between 3-5 ppm your water will stay blue.
It Should Not Be Done Together
This is because when you mix chlorine and algaecide together, it renders both of them useless.
In general, add one pound of shock to your pool for every 10,000 gallons of water. But if you're experiencing an algae problem, you'll need to add double, triple, or quadruple the amount of shock.
Yes, shock is the key ingredient to killing algae in pools. Shock raises the free chlorine levels in your pool water to the point where contaminants like algae die off. Depending on the severity of your algae growth, you'll need to add 2-4 doses of shock.
It's often recommended to shock your pool once a week. If you don't do it every week, you should at least do it every other week. This is necessary to maintain your pool's water chemistry. If you have a lot of people over in your pool or have a party, you may want to shock your pool more frequently.
Chlorine shock is usually the best way to get rid of green algae. However, an algaecide may become necessary if you're fighting more chlorine-resistant algae, such as mustard algae or black algae. Even then, the pool algaecide should work with chlorine or other sanitizers – not as an alternative to them.
Using baking soda in your pool is one of the easiest but most efficient ways to get your backyard ready for summer. This pool idea is loved by experts who recommend using this homemade remedy to increase the alkalinity and pH level of your pool – and treat black algal growth on your swimming pool wall.
Shock Your Pool with Chlorine to Kill Algae
This is the main event in clearing a green pool—killing the algae. Pool shock contains a high level of chlorine that will kill the algae and sanitize the pool. For the best results, use a shock that contains at least 70% available chlorine (calcium hypochlorite).
Cloudy or milky swimming pool water is caused by seven main issues: improper levels of chlorine, imbalanced pH and alkalinity, very high calcium hardness (CH) levels, a faulty or clogged filter, early stages of algae, ammonia, and debris.
It all depends on the cause and severity of the cloudiness. In general, it can take up to three days for chemicals to balance, or less if you use a pool clarifier. Keep testing, run the pump and adjust the chemical balance until your water is crystal clear again.
How long will it take to clear the pool? A fiberglass pool in its worst condition can be algae-free in 24 hours. For a vinyl liner pool, the process can take 3-4 days. For a concrete pool, this can take a week or more.
Green or Dark Green Pool Water:
This means there's a medium amount of algae in your water and you'll need to triple shock your pool. Triple shocking requires 3 pounds for every 10,000 gallons of pool water.
Dead algae has a distinct appearance, looking grayish in color and dusty when it accumulates in the bottom of the pool. Once the pool water is clear, it's easy to see down there.