Swimming pools are a brilliant way of cooling off during a hot summer. Of course, this isn’t a particularly original idea, and hundreds of people might use a particular pool every day. Chemistry is on hand to help prevent us from swimming in water that harbours potential water-borne infections. It can also help out with the cardinal sin of pool-peeing, though not without consequence. It does this, as you likely already know, through the chlorination of pool water – although it’s less simple than you might think!