Closing your pool for the winter is one of the most important steps in maintaining a pool properly. Do it right and spring opening is no sweat. Do it wrong and you could meet the creature from the black lagoon, up close and personal. Your choice of a winter cover is key to a successful pool closing. There are four types of generally available pool covers on the market today, each with its strengths and shortcomings. The main types are solid, mesh, mesh safety covers and solid safety covers.

Solid covers
Solid covers represent the largest number of pool covers sold in any given year. They are constructed of woven polyethylene tapes in what is called the scrim. Think of this as a flat piece of woven textile. This scrim then receives a coating of plastic on each side for waterproofing. While made by Canadian mills for many years most of these covers today come from Asia.

Advantages-Solid covers are relatively inexpensive and easy to install. When properly installed they do a reasonable job of keeping your pool clean and ready for the next season.
Disadvantages-The fabric is subject to wind damage due to flapping of the material, they collect water and debris and the methods to hold the cover in place can cause problems during the winter.

Mesh Covers
Mesh covers are made just like the solid covers but omit the plastic coating as they are designed to let water pass through.
Advantages-Mesh covers are lighter and less subject to wind damage. Water drains through so spring removal is easier and not as messy.
Disadvantages-By allowing water to penetrate mesh covers also allow fine dirt and sediment to penetrate and end up in the pool. Mesh covers also allow a small amount of light to reach the water, which can allow algae to grow as the weather warms toward pool opening time.

Safety Covers
A relatively new entrant, safety covers have gained a solid place in pool covers. They are called safety covers because they are recognized by the ASTM as preventing accidental access to a swimming pool when properly installed. To meet this standard the cover must support up to 4000 lbs.! They are constructed of a heavy-duty mesh reinforced with woven, heavy straps that cross the pools width and breadth. They are anchored with heavy-duty springs hooked to anchors that are drilled and set into the pool deck.
Advantages
Safety covers give invaluable peace of mind knowing the pool is secure from any unauthorized access. As they are built to a minimum standard safety covers offer reliable quality and very long service life; up to ten years and more. If you have a custom pool with a unique shape this is probably the cover for you as a large percentage of these covers sold every year are custom made.

Disadvantages
All this peace of mind and performance comes at a price. Safety covers generally cost several times the price of a solid cover. Only pools with a deck can use a safety cover as the anchors for the covers must be in concrete or wood. This limits the safety cover option to in ground pools or above ground pools with decks all the way round and a minimum of 2 feet in width. Safety cover mesh also lets fine dirt and sediment pass through which some owners find objectionable.

Solid safety covers
Made exactly like mesh safety covers except the solid vinyl is substituted for the mesh fabric. Only incorporating a small, sealable mesh panel for drainage the solid safety covers lets virtually nothing through when installed.
Advantages
In addition to the advantages of a mesh safety cover the solid covers allow no light to penetrate or debris to enter virtually guaranteeing a clean pool in the spring.
Disadvantages
These suckers are HEAVY! A solid safety cover for an average in ground pool tips the scales at nearly twice the weight of a mesh safety cover. This has recently somewhat minimized with new, lighter fabrics from some manufacturers. Solid safety covers also command a premium of roughly 15% above the price of a mesh safety cover.