The cover must be placed on the water during a period of cloud cover or in the evening hours. If this is not possible, the cover must be brought from an area protected from sunlight and placed immediately on the water. In this case it is important that the slats do not sit in the sun for any length of time before they are placed on the water, otherwise they will become deformed. If the solar / transparent cover is lying on the water: The water circulation (filter system) must be switched on all day long, otherwise heat will accumulate under the cover, causing the slats to age more quickly and possibly become deformed.