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.
Skin problems
Green algae, which are a common sight in unmaintained swimming pools, aren't harmful. However, the bacteria that feed on the algae can present a health risk to humans. Green algae exposure can mean bacteria exposure, leading to rashes and various breaks on human skin.
Exposure to blue-green algae during swimming, wading, and water-skiing can lead to rashes, skin, eye irritation, and effects such as nausea, stomach aches, and tingling in fingers and toes.
Skin infections are the most common health effects of swimming pool algae. Some adventurous swimmers expose themselves to algae that harbor bacteria. These infective agents can cause itchy rashes and breaks in the skin can even expose you to more severe infections.
Chlorine is still one of the most effective killers of algae so doing a super-chlorination of 10-20 ppm of chlorine can go a long way towards wiping out the algae. Liquid chlorine is an ideal shock for algae because it is fast acting and does not add cyanuric acid (CYA) or calcium to the water.
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.
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.
Ingestion: Gastrointestinal (GI) effects include nausea, vomiting, diarrhea, and mild liver enzyme elevations. The time to onset of GI symptoms after oral exposure is usually 3–5 hours and symptoms can last 1–2 days. Exposure can cause conjunctivitis, rhinitis, earache, sore throat, and swollen lips.
You'll always have algae in your pool, but a few things can kick off an algae bloom. 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.
Key messages. Algae-affected water may not be suitable for drinking, recreation or agricultural use. Contact with affected water can cause skin irritation, mild respiratory effects and hayfever-like symptoms. Ingesting toxins can cause gastroenteritis symptoms, such as vomiting, diarrhoea, fever and headaches.
If you've been working to clean your green pool but it's still green tinted, test your pool water for bacteria, chlorine, and pH levels. If they're within normal limits, and you have only spots of algae or a light green tint, it's likely okay for swimming while the water continues to clear.
Elevated nutrient levels and algal blooms can also cause problems in drinking water in communities nearby and upstream from dead zones. Harmful algal blooms release toxins that contaminate drinking water, causing illnesses for animals and humans.
There is no way to just look at an algae bloom and tell if it is toxic. Green Algae can be picked up when a stick test is done. If you poke a stick into the algae and the algae grabs on to the stick, is stringy and has a texture, this will tell you that it is a filamentous algae and it is safe.
Exposure to high levels of blue-green algae and their toxins can cause diarrhea, nausea or vomiting; skin, eye or throat irritation; and allergic reactions or breathing difficulties.
Cyanobacteria and their toxins can make people sick. In fresh water, such as lakes and ponds, harmful blooms are most commonly caused by cyanobacteria (also called blue-green algae), which are a kind of single-celled organism called phytoplankton. Some cyanobacteria produce toxins (poisons) called cyanotoxins.
Direct contact with algae can cause irritation to the skin, eyes, ears, nose and mouth. To be safe, people and pets should avoid water affected by algae. Do not use untreated algae-affected water for drinking, showering or washing. Boiling algae-affected water does not remove toxins.
Surprisingly enough, too much chlorine can also cause your pool water to discolor, but no algae can grow in water with high chlorine levels.
Apply 0.7 oz (20 g) of chlorine shock treatment for every 500 US gal (1,900 L) of water in your pool. Run your filter for 8 hours to circulate the treatment. Use a pool vacuum and clean out your filter to get rid of the dead algae leftover in your pool.
"Algae will take out all the ammonia [and] 88 percent of the nitrate and 99 percent of the phosphate from the wastewater — all those nutrients you worry about dumping into the receiving water," Lodge said in a statement. "In three to five days, pathogens are gone.
We have found that a cyanobacteria bloom usually dissipates within three weeks, though the same body of water may experience several individual cyanobacteria blooms over the course of a year.
Algae may directly infect humans and cause disease.
When temperatures reach below 40°F algae growth is stopped, but it can still survive and become dormant over the winter. Pool algae will come back to life weeks before you decide to open your pool.
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.
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.