I am a first pool owner and I just bought a dolphin M5. I clean it one day and the next day the bottom has dust and sand at the bottom. It says you can leave it just sitting in the pool and set it to run during the day for at least three days in a row. Do a lot of people tend to do that? I just wonder about it being exposed to the elements here in Michigan. However, I don't like the idea of having to bring out the Caddy hooking it up, putting it in the pool, running it and then puting it away and back in the garage. Does anybody leave ther robot pool cleaner in the pool and if so, for how long? Thanks!