Have your pool maintenance efforts suddenly taken a dark and unpleasant turn? Have you noticed some unsightly – and very stubborn – black spots taking up residence in your pool? We don’t want to spread any panic … but you may have black algae.

What is Black Algae?

Algae is algae – right? Actually no. While the term ‘algae’ usually refers to a type of non-flowering aquatic plant, black algae is not a plant at all, but a bacterium. The problem with black algae is that once it’s taken root in the pores of your swimming pool, it’s a devil to get out. It shows remarkable resistance to traditional cleaning methods and chemicals due to a thick scab-like covering which it uses as some pretty hardy protection. This, coupled with very insistent roots which embed themselves into the hard-to-reach parts of your pool, makes it one tough customer to get out, and keep out.

What Causes Black Algae?

While some undesirable swimming pool conditions may allow black algae to grow and flourish, it needs to get into your pool first. It’s generally accepted that black algae is often introduced by wildlife or dogs that have been exposed to the bacteria from other water sources, or from wetsuits or swimming costumes. If these water recreation items which have been used in a lake, pond or ocean where the algae is present are not washed out properly, then the black algae has a new home in your swimming pool.

If your pool filter is faulty, your pump does not run regularly for at least 8 hours a day, or if your pH levels are out of whack, then you are a prime target for these dark micro-warriors.

How To Treat Black Algae

The saying “Hit it hard and hit it fast” applies here. If you find these unsightly black spots in your pool, then be prepared for a lot of manual labour – there is no quick fix.

Chemicals alone won’t help your cause due to the layers of protective gear worn by these little critters, so you will need to grab a hardy bristle brush and scrub the dark spots. This removes their protective coats and allows the chemical warfare to begin. Once you are satisfied that you have scrubbed all the spots, rub each spot with a chlorine tablet – ensuring that you always wear protective clothing!

Directly after this, you will need to shock your pool (3x your usual dose of chemical) and follow this with a good algaecide.

These steps need to be taken one after the next for the process to be fully effective.

Yes, dealing with black algae can be a royal pain, and an awful way to spend your Saturday. So if you don’t fancy doing this yourself then give us a call – we can help.