Use chlorine tablets. Break a tablet in half and rub it directly onto the surfaces affected by black algae. This will help kill the roots and prevent it form growing back.
Metallic pool algaecides like silver algaecides are especially effective on black and yellow algae. Metallic algaecides are the most powerful of the three, therefore can be expensive.
Black algae only happens when there is a too low chlorine condition OVER A PERIOD OF TIME which means you have been letting your FC get to low and leaving it there. Bumping the chlorine high and then letting it drop before adding more will not keep black aglae away. You need to maintain constant FC levels.
The best way that would usually work is either carbon or hydrogen peroxide. These 2 chemicals usually are very effective in getting rid of algae. Also, a tip for getting rid of algae without using these tactics is to get a very hardy and fast growing plant.
Use chlorine tablets. Break a tablet in half and rub it directly onto the surfaces affected by black algae. This will help kill the roots and prevent it form growing back.
The black spot is only the top of the algae. This part can be removed, but it will generally regrow within a few days. Algal spores often take root on swimming pool walls and floors when the swimming pool is drained of water and grow when the swimming pool is filled with water.
Horticultural-grade Vinegar
Spray a mix of one-third vinegar to two-thirds water. It will not only kill algae but will help prevent it from growing back. In a nutshell, horticultural vinegar is more potent (typically 20 percent acidity) versus the 5 percent acidity of the household stuff.
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.
What Kills Algae Naturally? Certain plants and bacteria act as natural algaecides, helping to control algae populations. These include barley straw, which releases compounds that inhibit algae growth when it decomposes, and beneficial bacteria, which consume algae. When using natural algaecides, patience is key.
Is there a fish that eats black beard algae? Yes, Siamese Algae Eaters, Otocinclus, Chinese Algae Eaters, Florida Flagfish, and Flying Foxes are all known to efficiently remove black beard algae. Consider using Nerite Snails and Amano Shrimp as well.
It seems that opinions are divided on whether black algae is harmful. There are sicknesses associated with water infected by black algae, but it appears that they are not directly related to the cyanobacteria but rather to other microbes that make themselves at home in and around the cyanobacteria colonies.
Black spot algae in pool surfaces are unique because it grows in the walls or floor of your pool, often in areas with low circulation and will not brush away like other algae. This algae type spreads slowly and is often mistaken for mold because it forms dark spots on the pool surface.
Black Brush Algae - BBA (Audouinella sp.)
Often called as Black Beard Algae - this is a very difficult type to get rid of! The small black, dark-grey or reddish hairballs will grow in clumps or patches of fine black tufts with a length of half a centimeter.
Poolife Super AlgaeBomb 60 Algaecide is the strongest, non-copper pool algaecide and is ideal for winterizing pools. Poolife Algaecide 90 Algaecide kills algaecide quickly and prevents new growth for up to 90 days.
Vacuuming will not get rid of algae. You need to SHOCK the pool and actually kill the algae first. After that, you can begin brushing/vacuuming/getting your chemicals back in balance.
Let the shock try to fight the algae first. Add algaecide about 24 hours after shock to finish the job and prevent future algae blooms.
Baking soda, also known as sodium bicarbonate is naturally alkaline, with a pH of 8. When you add baking soda to your pool water, you will raise both the pH and the alkalinity, improving stability and clarity. Many commercial pool products for raising alkalinity utilize baking soda as their main active ingredient.
Vinegar is less potent than bleach, but if you have a mild roof algae problem, it can work well while being less harsh on your shingles and the environment. Mix equal parts white vinegar and water, spray it on the affected areas, let it sit for 15–20 minutes, and rinse with water.
H2O2, or hydrogen peroxide, is a powerful oxidizing agent that can be used to kill algae in water. When added to water containing algae, H2O2 breaks down into water and oxygen, releasing free oxygen radicals in the process.
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.
Remember, if black spot stains are left for longer than 2-3 years, the algae roots can sometimes penetrate the pool interior and discolour your pool surface permanently.