Pool cover question...

What is the diameter of the pool? (assuming it is round) larger diameter pools may need a air pillow but it is not necessary for smaller diameter ones.

You do need to pump pump the water off the cover or you will get a really nasty mix on the cover. Mosquitoes and flies love this standing water as well.

The weight of the ice and snow can also cause the pool walls to collapse.

I have always used a pillow though I am not sure if it is neccessary, it typically (mostly) deflates within the first few weeks anyway and it never stays in the middle. I guess it can't hurt anything other than the (fairly minimal) cost.

The water on top is kind of a balance in my experience. You definitely want some to help keep the cover from parachuting on windy days, but it can also get nasty. I will drain/pump it off a few times during the offseason just so it doesn't get stagnant or too heavy and pull on the walls. If there is a really big snow, I will often go out and just push a lot of it off with a shovel or even the pool brush on the pole. You just have to watch it and be consciousl of it ever putting too much tension on the walls, though I would think (hope!) the cover would rip before collapsing a wall.

We have a 24' AGP that has around 13,000 gallons. Have had good luck with doing it as your directions state, with one exception. We add an air pillow inflated about 75% to allow the forming ice to push on the pillow instead of the sides of the pool. Sometimes the pillow breaks, other times it has lasted 3 years before developing a slow leak. But for $15-20, it's kinda cheap insurance. I try not to let any excessive water (some is ok) sit on my cover. Water on top of the cover doesn't know it's on top; it just combines with your pool water depth under the cover and may cause an overfill situation, which you want to avoid. I use a small submersible pump and garden hose to occasionally siphon it off. If we get heavy snow, I will try to remove as much as I can reach, but be careful; don't punch a hole in the cover while doing this.

Hope this helps.
G.