How we look after the water, twice a day

Parents often ask about the water before they ask about the coaching. They are right to. Here is how our pool is looked after each day.

At 5 am, an hour before the first batch, Ganesh, who runs our plant room, tests the water at three points in the pool with a simple kit. He checks two numbers. Free chlorine should be between 1 and 3 parts per million, enough to keep the water clean without stinging the eyes. The pH, which measures how acid or alkaline the water is, should be between 7.2 and 7.6. If either is off, he adjusts the dosing before the pool opens. The readings go into a notebook kept at the lifeguard desk, and any parent can look at it.

The water is pumped continuously through sand filters, which catch hair, dust and fine particles. The whole pool passes through the filters about every five hours. The filters are backwashed every two days, and the pool floor is vacuumed every night after the last batch at 9 pm. The tests are repeated at 2 pm, before the afternoon batches.

Swimmers help too. Everyone showers before entering the water, which removes sweat, oils and lotion that use up chlorine. Children go to the toilet before class, and caps are compulsory. A strong chlorine smell, by the way, does not mean too much chlorine. It usually means the water needs more, to break down what swimmers have brought in.