Care for the cover
The benefits of pool covers are indisputable - they save on energy by trapping heat in the water, provide an element of safety, help save water and reduce chemical quantities required to treat the water. But just like every other component of a pool, the cover requires maintenance to ensure longevity and optimal performance. Pool+Spa discusses pool cover maintenance with David Lindner from Sunbather.
There are several pool cover types, including polyethylene bubble, polyethylene thermal and PVC rigid slat. These types of covers are susceptible to damage from various elements; however, they are all damaged in some degree by the oxidising effects of chlorine. The use of a cover promotes higher chlorine levels because chlorine is retained by the cover. Chlorine consumption is therefore greatly reduced with cover use and so needs to be administered to the pool at a reduced dosage rate. Excessive chlorine manifests as bleaching and embrittlement of the plastic material.
Bubble and thermal covers generally fail due to chlorine effects on the underside before the sun-exposed side fails, as UV resistance is generally good for all three types.
A major downside of bubble materials is thermal degradation, which occurs if bubble covers are left on rollers without a protective over-cover to stop the sun from penetrating through the layers. Internal temperature build-up within the layers will expand bubbles and delaminate them from the base material. This can happen in one hot day.
All cover types should be stored on suitable rollers as this is the only practical solution to keep them flat and prevent damage caused by folds, creases or chafing. Rollers should include additional length beyond the cover width so that some ‘run-out’ can be accommodated on the roller without edge damage to the cover.
In a commercial situation where starting blocks are installed, it is advisable to locate covers and rollers at the opposite end of the pool to minimise cost of roller equipment, operator effort and possible damage. If there is no alternative to starting blocks, then the rollers need to be fitted with a starting block extension roller to carry the covers over the starting blocks.
The life expectancy of a well-maintained pool cover varies with the type of cover installed and also the frequency of use. It is best if people use their warranty as a guide for this.
According to Lindner, when it comes to pool cover maintenance there are several mistakes pool owners/maintenance technicians make. For example, with commercial pools, a lack of planned operation is a huge mistake as is a lack of staff training in handling the covers. In a domestic situation, where bubble covers are applied, the biggest mistake is to not place a protective cover over the bubble cover when it is off the pool.
With thermal covers, the biggest mistake is to try to manhandle the cover without a suitable roller system or to over-chlorinate the pool with the covers on. With rigid covers, the biggest mistake is to not strictly maintain water level in the pool at all times.
Considering cover issues at the planning stage
When constructing a new pool, owners and pool builders should consult with pool cover professionals from the start so that cover installation issues can be avoided and space can be allocated for cover storage when not in use, so as to meet client needs.
“A lot of customers are doing their homework and deciding on what pool cover system they want to include before they even choose a pool builder. This ensures that the customer gets a system that they are happy with and it is included on the plans and not retrofitted or as an afterthought taking away the options to hide or enclose the system,” said Lindner.
When constructing a pool, other factors that impact on the choice of cover are:
- Is the pool going to be heated with solar or fossil fuel heating? If so, the customer will want a heat retention cover, a thermal or rigid slat.
- Does the customer require the system to be fully automatic? If so, then the pool should preferably be rectangular or at least a simple geometric shape to suit most fully automatic pool cover and roller systems. The most popular being the rigid slat cover. This cover can be housed in a concrete wet pit at the end of the pool that is formed with the pool shell, or if retrofit, will sit above the pool surface at the end of the pool.
- Thermal covers and bubble covers can also have automatic rollers. These are quite often housed in dry pits at the end of the pool or on fixed end frames at the end of the pool and then have an enclosure built over the top.
- What is the client’s budget?
“If all of the manufacturer’s instructions and recommendations are followed, pool cover and roller systems are, as a rule, very low maintenance. Sunbather recommends that all covers have an annual service carried out on them,” said Lindner.
Repairing pool covers
When it comes to repairing damaged or ageing pool covers, not all pool covers are equal. Some covers can be repaired while others cannot and this comes down to the composition of the blanket.
Repairs to polyethylene covers, be they bubble or thermal, are mainly limited to wear or damage around edges by sewing or use of brass eyelets to rivet patches or reinforcements into place although this can be messy and unattractive.
There is no adhesive available to glue patches or reinforcements to polyethylene. Bonding is always achieved by fusing surfaces together during the production process with specialised equipment. Old sun- and chlorine-affected material does not weld reliably using this technique.
Slat covers can be repaired, principally by replacing individual slats.
Commercial scale covers are generally best repaired on site given size and difficulties encountered in packaging prior to freighting, not to mention the cost of freight itself. Repairs are done with patches and eyelets.
Commercial covers can have fraying edges replaced as the blankets near the end of their life and the operator needs to get another season of use from them. These can usually be sewn or otherwise attached on site and will allow continued use.
Maintenance on a commercial pool cover
When it comes to commercial pools, there are a number of factors which need to be considered to maintain the expected life of a pool cover.
- Pool cover width should generally be no more than 6 m and preferably no more than 4.5 to 5.5 m to facilitate handling. Wide covers (6-10 m) will minimise roller numbers but make the job hard for operators and can suffer with stretch and creasing issues.
- Pool cover handling on and off the pool needs to be orchestrated for consistent results regardless of staff numbers and shifts. Things such as accurately defined roller positions (using a drop bolt system) will reduce the effort and time required to roll out and pack away covers and minimise cover damage.
- Roller mechanisms need to be structurally capable of handling covers in the first instance, which is not always the case, and with sufficient mechanical advantage to enable operation either manually or with a machine having regard to occupational health and safety considerations.
- Covers need to fit easily onto rollers to, once again, allow for cover run-out should covers tend to cone over the 25 m or 50 m run. This will reduce damage to cover edges.
- Cords attaching covers to rollers need to be replaced when broken as uneven pull along edges can create creasing into the cover, which once created can never be removed and can result in a cover which converges and layers on itself making it unmanageable.
- Covers need to have buoyant leading edges which keep the cover ‘planing’ across the water surface, not leading edges which sink when being pulled creating big drag loads: bad for covers and bad for operators.
- Tailoring covers to fit between the lane ropes bounding two lanes where possible will reduce wear and tear and also makes the operator’s job easier.
To caretakers of commercial pools Lindner explains, “If the above considerations are observed, maintenance should be minimal. Maintenance revolves around proper handling. There are annual maintenance contracts available which should be put into place.”
Top 5 tips for pool blanket care
- Do not allow covers to crease when loading them onto rollers. Creases are extremely hard to remove once ‘ingrained’ and make cover handling more difficult.
- Always replace broken roller attachment cords: the absence of cords can promote creasing.
- In extremely windy conditions (eg, gale force), covers may need to be removed from the pool prior to the event to avoid being blown away and subsequently damaged. The security straps supplied with covers are a must under these conditions.
- Do not administer concentrated chemicals (eg, chlorine) next to or onto covers as they may suffer damage.
- Lane ropes can remain in the pool while covers are in use but will lead to some level of wear. This is generally acceptable but broken lane rope segments can be quite damaging.
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