Long-term operation of swimming pools with acrylic glazing is possible only with proper and regular maintenance. A special attention should be paid to the preparation for winter cold of open-air objects which are located outside and are not operated in the cold season. Before frost days come, such objects should be properly preserved. The complex of measures for winter preparation should be made in advance to an outdoor pool in the winter was fully protected from an influence of low temperatures. It is not necessary to start the preservation too early because a long stay of liquid in a stationary state at zero temperature can lead to the development of microorganisms. The same can be said about the system of spring re-preservation — it should be carried out when the temperature will be firmly fixed on a positive note.

Pool preservation above ground level

The pool which is located above ground level, should stay without water in winter. Draining is carried out, if the bottom is at ground level, and its walls does not touch the ground. When freezing water expands considerably in volume, which is fraught with partial deformation or even rupture of the walls, not only acrylic glazing but concrete casing too. Besides, at low temperatures suitable material is less durable and more brittle, which creates additional risk of structural destruction. If the tank is not empty, hopelessly spoiled will be not only walls, but also filtering equipment.

During the whole winter period the ice is freezed and melted several times, the load on the walls and on the acrylic glazing is distributed unevenly, increasing the chance of tearing or deformation of the walls. And even if the tank is not destroyed during the first winter, after two or three seasons at the surface will develop cracks. It is important to realize that the frost by itself is not dangerous for acrylic and the risk of destruction can be associated only with the exposure of the ice or ground on the walls. Frost resistance of acrylic is at a sufficient level to keep its strength characteristics even at low temperatures.

Pool preservation below ground level

Pool, partially or completely buried in the ground, in the cold season should be filled with water. Frozen ground also increases in volume, creating a high load on the wall from the outside. Water creates pressure on the walls from the inside, acting as the counter force. The pressure level is partially balanced, the integrity of the walls is preserved. Construction of swimming pools with acrylic glazing implies the presence of glass walls, partitions, underwater windows without contact with the ground. If the main part of the object submerged in the soil, the drainage of the liquid during freezing is prohibited. The frozen liquid can squeeze acrylic panel, the load of which is not balanced by the pressure of the soil. It can occur that the water drain and its presence in the tank can lead to undesirable consequences.

It can be solved easily: winter pool preservation is made in combined way. Such way does not exclude the use of the water column as a reliable force opposing the pressure of the soil in the recessed areas of the tank. But to this liquid, turning into ice, does not destroyed acrylic panel, it is necessary to take additional measures to reduce pressure on the glass. The most effective method of reducing the load on the acrylic glazing is the use of volume expansion compensators – special elements that can significantly compress with increasing pressure level. Compensators take most of the load, the pressure on the acrylic panel is minimized, the glazing remains intact the whole winter period.

Installation of volume expansion compensators

As compensators can serve special floats, 80% submerged. Such products look like kind of hermetically sealed pillows filled with a small amount of liquid or sand. The advantage of such products is that they can be used repeatedly for many seasons. In addition, the design of floats suggests the possibility of their simple and reliable connections with each other. Certainly, the use of specialized floats-compensators is preferable, but it is possible to use other, more available improvised means. As compensators can be used air-filled plastic containers, partially inflated car tyres, air-beds, foam panel, large plastic bottles and other receptacles capable to be compressed under the action of pressure. 

It is necessary to bind the weighting with sand or fill a quarter of small stones to stop popping up of such compensators above the surface. It is not a good idea to use sand to fill such containers because the plastic can be broken with frozen water, and fallen sand will make the spring re-preservation more difficult.

The floats should be placed around the perimeter, or like two intersecting diagonal lines. Protection of acrylic glazing should be heavily enforced. The glass wall should be covered with Styrofoam panels or fencing with dense chain of connected floats-compensators. If the concrete walls can be protected by only half of the perimeter, acrylic glazing should be protected over the entire surface. Expansion joints must be related, extreme elements attached to the walls. Loose floats can gather in one place – in this case, their effectiveness will be minimized. For tying the weights should not be used a metal wire – it is better to ruse synthetic twine.

Water preparation for pools preservation

For proper pool preservation it is necessary to change water. It is prohibited to freeze the water that was in the tank all the summer. A pool should be emptied and walls and equipment elements, that have a contact with water, should be carefully cleared from the water plants, mineral deposits, grease particles and other impurities with the help of special tools and instruments. Acrylic panels should be cleaned according to the recommendations of the manufacturer. Cleared surface should be rinsed with a small amount of water, the remains of which must be manually deleted. It is impossible to left even the smallest particles of detergent at the bottom for the winter – they can seriously damage the surface of the walls and acrylic glazing.

The special cleanser for preservation should be added to water. It will prevent the activation of development of algae and other biological processes in a humid environment. This is a very important operation, which provides clean water in case of the late winter. If such cleanser will be not added, the object will need a serious cleaning in spring. Before freezing there can be more than one day or even a few weeks – during this time, while in the tank will be standing water at the bottom may form a significant layer of lime and salt deposits. One more composition for preventing deposition of sediment in stagnant water should be added to avoid such a situation. To mix a solution completely and to wash a pipeline, it is necessary to activate pumping equipment for 12 hours. As a result of such cleaning pH level should be 7,2-7,4.

How to prepare pool equipment for a winter

The process of filling with water consists of several stages. First of all a clean and dry tank should be filled to operating level. Then a filter should be activated in normal mode for two-three hours. After flushing the system, water should be drained so that its level has dropped by 10-15 centimeters below the bottom of the injector, so the liquid from the pipe was free to go. If the object is buried partially in the ground, the water level should be below ground level at 10 cm. These several centimeters should be left for possible upgrade of the ice level in a case of extension. If not leave it stock, then ice may rise above ground level and the water pressure will be without opposition from the soil.

Built-in lighting devices should be removed, the wires should be put out of the pool and carefully insulated. Preservation of the filtering system includes the following operations: filter work in a special mode of intensive backwash for a few minutes, filter seal for a few seconds and it returns to the filtration mode. Also it is necessary to follow the manufacturer’s instructions for the filter washing. Just before the preservation a filter should be disconnected from the system. All the hydro-system details should be removed. The details which can not be removed have to be cleared from the water and closed with plugs made of foam and wrapped in polyethylene with a small amount of air. It is preferable to open the valves of all the pipes. Dismantled equipment is carefully wrapped with a cloth wrapped in plastic and sent to storage in a dry warm space.

The construction of a shelter for the pool

After finishing of all stages of preservation, the tank must be covered with a special tent. A special pavilion made of polycarbonate, plastic or wooden Board, canvas stretched on a metal frame can serve like a shelter. The construction of a shelter have to be strong enough to withstand the pressure of the snow layer. It is important that tent does not rest on the pool sides, because the goal of all conservation measures is to reduce any loads on walls and glazing. Shelter protects from snow, debris, rain and ultraviolet radiation. Shields, initially not adapted like the shelter of the pool can be used only if they do not rely on the sides. It is better to use special tents. Ice in the tank have to serve its original form. It is important not to break its integrity, since the fragments can damage the surface of the acrylic panels and other work surfaces.

It is possible to make the pool preservation by your self or engage a specialist who knows exactly how to preserve the pool for the winter, in that case the work will be done more effectively and efficiently.