I love that I can bring a sample of pool water into them and they will tell me everything I need. I have found though that when I stopped using them to buy all my chemicals and was able to discern the readings myself that we saved alot of money. Seems like sometimes they go overboard with what they want you to put in it. They are very knowledgeable, but watch out that you don't think you HAVE to buy all of that for your pool. Get to know what you're buying and just go there for your water readings.