I have an internal leak of sand from my sand filter that puffs out a little bit each time the pump starts. It's not really noticeable after one or two starts but eventually a small pile develops beneath one of my returns. During the summer when I'm vacuuming frequently there's hardly evidence of the problem. Now that it's winter, and it's generally too cold to vacuum, a sand pile has developed. Is there any harm leaving sand in contact with plaster over winter? The media is Unimin #20 filter sand.