June to September: when chlorine cannot keep up
Summer chemistry is a losing race that you manage rather than win. Ultraviolet light destroys free chlorine, and hot water accelerates every reaction, so a dose that held for days in January can be gone within a day in July. The standard defence is cyanuric acid, the stabiliser that shields chlorine from sunlight, but the UAE has a particular trap here: trichlor tablets add stabiliser with every tablet, and by late summer many villa pools are so over-stabilised that the chlorine reading looks fine while the water is barely sanitised. A competent technician tests cyanuric acid monthly in summer and dilutes with fresh water when it creeps too high.
Frequency has to rise with the temperature. A pool that was fine on one visit a week in February generally needs two in August, with the technician brushing walls, emptying baskets, backwashing more often and adjusting dosing at each visit. Pump run times should stretch too: eight to ten hours a day in high summer is typical, against four to six in winter.