Just wanted to touch on a couple of concerns pool owners in Las Vegas have every winter.  The most commonly asked question I get is:  "How long do I run my pool in the winter?"  I always respond by telling them the most important thing is not how long to run the pool, but when to run the pool.  You see, even though we live in a desert that during summer months is hotter than Haiti, during the winter it does get cold here and often times freezes!  So when you need to run your pool in the Las Vegas area in the cold months is always at night.  The minimum run time I recommend is 6 hours; from midnight to six in the morning.  Ideally, the best would be from ten at night until eight in the morning.  That is ten hours of run time, but it also assures you that your pool water is circulating during the hours of the most potential for freezing.  As long as the water is flowing through the pump, filter and all of the plumbing during these hours, you will almost guarantee eliminating the risk of pipes freezing and the potential risk for costly repairs.