Having a pool algae is never okay. Although it is not really harmful to swimmers, it can become a breeding ground for harmful pathogens like E-coli. It can also compromise the filters in the water. And besides, nobody would want to swim in a pool that is filled with algae.

But how does an algae bloom happen? This is a marine creature that can multiply quite rapidly if the situation is right. All it needs is the sun, carbon dioxide and it can bloom overnight. It can be caused by the rain or a contaminated swimsuit or equipment. Usually, this can be avoided by having the right balance of chemicals in the pool. However, there are times when neglect happens and poor circulation, damaged filtration system, and unsanitary habits can make your pool a haven for algae.

Fortunately, there are ways for you to treat pool algae. But you have to check the color of the algae. The treatment that you will use will depend on it.


The most common algae to be found in residential swimming pools is usually green. This usually happens when the sanitizer level of the pool is too low. It can also appear when there is poor circulation. Fortunately, you do not have to worry because this is the type of algae that can be easily removed. You simply have to raise the chlorine level in the pool. You can also choose to add some algaecide. You should also clean any swimsuit or pool toys that will be used before swimming in the pool.


This looks like black dots in a pool plaster. If the plaster used in the pool is pitted or etched and if calcium deposits developed there, these can be breeding grounds for black algae in the pool. The more dilapidated the plaster, the higher chances of black algae. If the water circulation in the pool is not okay, then this problem can escalate. Unfortunately, it is not possible to completely eliminate this. The best you can do is to control it. To do this, you have to scrub the area where the black algae appeared. This might take a couple of tries for it to completely disappear from sight. You should also treat the surface with “trichlor” and copper-based spectrum algaecide. You should probably have your pool water tested after the treatment. You do not want too much metal in it because it can already be harmful to swimmers.


Sometimes, this type of algae turns a mustard color. This is admittedly, the most challenging to remove. It is also hard to diagnose. If your pool water looks blue, this type of algae might look green to you. That could lead you to give the wrong treatment. Not only that, it might be mistaken for pollen or dirt. To know if it is yellow algae, you have to scrub it. When it sinks to the pool floor, that is pollen. But when it reappears on the side of the pool, that means you are dealing with yellow algae. You have to find a chlorine enhancer that specifically targets yellow algae in the pool. This is the only way you can solve this problem. You should also take note that once something is contaminated with this type of algae, it can easily return. Even swimsuits, equipment, and toys should be treated to remove the algae. If a previously contaminated toy is brought into a pool, the yellow algae can easily bloom once more.