Something to add here, and any recommendations are most appreciated. My returns are 18" below water surface and my light is 24"-34" below the surface. So if I was going to take this tact I would want to drain 38" of water from the pool?! Wowza. Or would I try to shoot the razor thin margins between under the returns and above the light. Or would I do what seems right and drain to a level half-way between the returns and the skimmer mouth just for the sake of keeping water out of the skimmer. I know I won't get a gargantuan ice block here in southeast PA but I will get an ice block. I'm honestly not sure what to do. When I got the pool it had evidence (water line) of resting at about that level for a number of years.