Don't drain it completely
A common mistake is leaving the pool empty all winter. An empty pool can lift under groundwater pressure; the lining and grout also dry out and crack. The correct approach is to lower the water level below the skimmer mouth and overwinter the pool full.
The real risk is in the pipework
It isn't the pool that freezes, it's the pipework. When water left in the pump body, the filter vessel and the pipes freezes, the housing cracks. So at closing, the lines must be drained completely and the pump taken out of service.
Frost is rare on the Antalya coast but it does happen; inland and at altitude it should be expected every year.
Winter chemical balance
Before closing, the water is balanced and a winter algaecide is applied. The aim is to suppress algae growth through the winter. A pool closed out of balance turns into a green pond by March and has to be drained completely at opening — a cost in both water and labour.
- pH brought into the 7.2–7.6 range
- The pool is shocked and the chlorine level allowed to fall
- Winter algaecide is dosed
- The filter is backwashed and cleaned
- The water level is lowered below the skimmer
- Pipework and pump are drained
- The winter cover is laid and secured
The one thing to do over winter
If the closing was done properly, no intervention is needed through the winter, but the state of the cover should be checked monthly. A cover that loosens in a storm or collects water both tears and dirties the water beneath it. Draining rainwater collected on the cover is a simple job that is routinely neglected.