Cleaning your pool after a storm or a trip away

Three things to observe before touching anything:

• Water colour: clear, milky, green, brownish?
• Deposits: leaves, sand, soil, green traces.
• Filter pressure: if it's abnormally high, clean the filter before cleaning the pool.

Run a full water test. What you measure decides your treatment.

Brush from top to bottom, walls then floor. The deposits get stirred back into suspension: that's normal, the filter will catch them.

Let it settle for 2 to 4 hours with filtration off. Then vacuum manually (not with a robot) on the waste setting rather than filtration: this sends the deposits straight out without clogging the filter.

It's quicker than you'd think: 30 to 45 minutes for a standard pool.

1. pH first, between 7.2 and 7.6. 2. Shock treatment with unstabilised chlorine. 3. Continuous filtration for 24 to 48 hours. 4. Curative anti-algae treatment if the water was green. 5. Flocculant if the water is still milky after 24 hours.

Don't skip the pH step: it's what makes the shock treatment effective.

• After a storm: rainwater drops the pH suddenly. Measure and correct this first.
• Olive-tree pollen (May-June): forms a yellow layer on the surface. Surface skimmer net then flocculant.
• Prolonged mistral wind: sand, soil, plant debris. Longer brushing and vacuuming.
• After a holiday: if the water is green, allow 48 to 72 hours to get it back on track. If it's very green, a professional pool clean is quicker and cheaper in products.