The pools in winter
Every pool owner for private or professional purposes, with the onset of winter when the facility is not used, start to wonder;''What am I doing now?".
A first and absolutely advisable technical - and not only - answer to the question is that a pool does vacate never !!! We apparently know that many will disagree because of their ignorance, however consider our point of view below.
The species of pool encountered in the Greek market which are related with the reservoir are the following:
? with reinforced concrete internally sealed with cement mortar and color or alternatively with tile or psidida
? with reinforced concrete internally sealed FILM LINER PVC
? prepared internally sealed FILM LINER PVC
In all these cases above the probable drain may cause irreparable damage.

The concrete in the absence of water will be exposed to rapid contraction-expansion due to a large temperature declinations, which may lead to cracks or BOTTOM coat.
The mortar will follow the expansion of the concrete and will crack somehow, like the tile sticking onto this.
The film case of material will have on the instructions of the plant's production to be located always in the water, differently it corrupts quickly,and  within 3-4 years it has been destroyed.
In the obvious question, how to keep the pool full, our opinion is that there are two solutions:
A. NET FULL & B. & FULL WITH GREEN WATER
and because no one likes the second option, we like to recommend you to keep the recirculation in operation for 1-2 hours every day (optionally one in the morning and the afternoon too) and add a tablet 200gr per week per 50m3 water. That is enough!!!
The money you pay in current is much less than what you would pay for cleaning and replacing the water. An indicative pump 1HP 6 months for 2 hours a day will consume 126kWh, or 25efro.