Whenever I install a new swimming pool for a client, I always tell them they need to shock the pool regularly. I’m often met with a confused expression, and some wits suggest creeping up behind the pool at night and shouting “boo”. I’ve heard this a hundred times now!

Shocking a swimming pool is a simple, weekly pool maintenance task that everyone should be carrying out, especially if the pool is used frequently, or if you have just been through a heatwave.

Shocking is also known as “super chlorinating” – i.e. adding a large amount of chlorine in one go. The process allows you to destroy any bacteria or organic matter in the swimming pool – and of course, you shouldn’t go in the pool once you’ve shocked it for at least 12 hours.

So – how do you shock your pool? Well, pool shock is granular, so you have to dissolve it first – you don’t want the granules sinking to the bottom and having no effect. Ensure that you add the pool shock to the water, and not the other way around. Stir the recommended amount of pool shock into a bucket of water, and stir well.

Next, you need to know how to start your filtration system, and find the return line fitting – if you don’t know where these are, ask your pool construction company. The return line is the point where water enters the pool, and you should see a stream of water coming out from it.

Pour the shock mixture into this stream slowly, so that it has the chance to mix properly into the water. And remember, this is a lot of chlorine, so leave at least 12 hours between pouring and re-using your swimming pool. Do this weekly, and you’ll ensure that your swimming pool remains bacteria-free.

Vaughan Turney owns Ascot Pools, a swimming pool construction and maintenance business in the south-east of England.