Adding shock to your pool super-chlorinates your water. And this extra dose of sanitizer will kill algae growth. The more serious your pool algae problem, the more shock you'll need. We recommend using calcium hypochlorite shock, or cal-hypo shock, as an effective algae treatment.
Bleach is great for killing algae (and other organisms that may lurk in your tanks) and for keeping it from coming back.
Apply a mustard algaecide following the label directions. Allow the water to circulate for 24 hours. Use a pool vacuum or backwash the pool again to remove the remaining dead algae. In persistent cases, brush the pool and apply algaecide once more after two to four days.
You could have inadequate filtration for your pool's size or low or inconsistent chlorine levels. Bad water circulation with dead spots or pool imbalance in your pool chemicals are also two big culprits. One or any of these factors can kick off a pool algae bloom that spreads across your pool.
Scrub the black algae away with a good, stiff pool brush. This will help break down the protective layer and make it easier to treat. Break a chlorine tablet in half and rub it directly onto the affected areas. The chlorine treatment will kill the algae's roots and prevent it from coming back.
Whether mild or severe, it isn't recommended. Significant amounts of swimming pool algae welcome a breeding ground of harmful bacteria that feed on algae. These bacteria pose health risks to swimmers, most commonly resulting in a skin rash. It can also cause various bacterial infections of the ears or eyes.
Shocking your pool with chlorine can be an effective method to kill algae. The process can take up to three days and we recommend checking with a pool professional for the amount of shock you should use for your particular pool.
Shock Your Pool
Shocking is the process of adding chemicals to your pool to raise chlorine levels and kill bacteria and algae. We recommend using a calcium hypochlorite shock to treat your algae problems.
If the pH becomes too high (over 7.8), it prevents the chlorine from doing its job. If you're not checking the pH and it has risen too much, you could be adding the right amount of chlorine, but it can't work correctly, and algae will begin to grow.
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.
You can use baking soda in a pool for two primary purposes: to increase the alkalinity and pH level for clear water and to cure black algal outbreaks on your wall. The founder of Cleaning Green LLC, Alicia Johnson, explains that baking soda (or sodium bicarbonate) has a pH level of 8, meaning it is a natural alkaline.
Algae create a chlorine demand in the water for itself, consuming chlorine that should be working on other contaminants. As it expels carbon dioxide, the pH level of pool water can rise. Algae are kind of like weeds in your garden.
Can you over shock a green pool? No. The more chlorine shock you add to a green pool, the better chance it has to kill off all the algae. Follow the normal shock treatment based on the size of your pool and you can double, triple, or quadruple the dose to kill algae.
It may surprise you to learn that algaecide isn't a magic bullet for getting rid of algae in your pool. In fact, algaecide is more effective as a preventive measure than a treatment. Don't get us wrong—it still helps as an algae treatment, just not in the way you might think.
Barley straw is a natural way to fight algae. On contact with water, the straw starts to break down, and as it does so it releases peroxides into the water which combat algae. Available in mini bales, or as a concentrated extract of barley straw liquid, it's a natural way of chemically fighting algae.
It Should Not Be Done Together
This is because when you mix chlorine and algaecide together, it renders both of them useless.
Most Algae Grows in High-pH Environments
Most types of algae typically enjoy higher pH levels, ranging from 8.2 to 8.7. Once algae starts growing, it can further raise the pH level in your pool and cause more algae growth.
While the rain itself doesn't generally harm your pool, it can dilute the carefully balanced chemistry in the water. This can alter your pH levels and dilute the chlorine or other sanitizers, allowing algae or other contaminants to gain a foothold.
Rainwater itself does not cause algae, but it can provide the right environment for algae.
A word on Filtration. If your filter is not running long enough per day, or is undersized, old or ineffective, this will exacerbate an algae problem. Effective filtration is operating the pump long enough so that all of the water in the pool is filtered at least once per day.