The water level in my agp is about level with the skimmer bottom. And on top of the winter cover there's a layer of about 4-6 inches of water and ice. Should I lower the level of water on top of the winter cover or the water off the pool, or both? And in which order if it makes a difference. Temperatures are forecast to drop to 20° and I want to avoid damage to cover, skimmer, etc. Any advice will be appreciated.