Winter cover
Also called: winter debris cover, scrim cover, pool winter cover.
A winter cover is a debris cover for a closed pool: it keeps leaves and light out and holds water on top, and it does not hold a person or a pet. No above-ground winter cover, mesh or solid, is a safety cover certified to ASTM F1346.
Why it matters
On an above-ground pool the wall decides the cover. A steel- or resin-wall pool with a top rail takes a scrim winter cover, held on by a cable through its grommets and tightened with a winch. An Intex, Bestway or other metal-frame pool takes a ratchet-strap fabric cover instead. Buy a scrim cover on its scrim count, not its warranty years, which are pro-rated. The cable goes tight and the fabric rests on the water. On an in-ground pool a solid winter cover lies flat on the water and is ringed with water bags; Blue Wave's inground instructions say not to use bricks or sharp blocks.
In numbers
The scrim ladder runs 7×7 (a season or two), 8×8, 10×10, up to 14×14 for snow country. The warranty years on the box, 8, 12, 15 or 20, are pro-rated: after the first year they pay a shrinking discount on your next cover, not a new one.