For appearance and safety, a mesh cover from LoopLoc or Meyco is best. (Google their sites). But, you have to maintain the water underneath, because they are NOT opaque.

Mesh cover pluses: safer, much nicer looking, longer life (10+ years), with practice quick and easy to install.
Mesh cover minuses: more expensive, block light but do NOT stop the pool from getting slimy if you don't maintain the water.

By the way, an all black cover will last longer (the green threads die from UV after 8+ years), but costs more.

A fairly easy way to use them is to install the cover when you're done with the pool, clean up the water, but do NOT winterize. Set your timer to run just a couple of hours per day, and continue maintaining the water. Do not actually winterize till freezing weather is on the way. Make sure the pool is ABSOLUTELY algae free before winterizing -- this is pretty easy to do with the cover on, since a shock dose of chlorine will last for days, with most of the light blocked.

Close with a double dose of Polyquat. Pour a dose of chlorine bleach into the pool every couple of weeks till the water gets really cold -- rinse the cover with a hose. Unwinterize and start the pump back up as soon as freeze danger is past. But do NOT uncover the pool till you are ready to swim.