Very disappointed in this. I have a brand new saltwater pool. Tells me my levels are off all the time & that we shouldn’t swim in it but when I take my water to a pool store to be tested everything is fine or just needs a little of something. I add what’s needed and it STILL says it’s not swimmable. Doesn’t measure chlorine levels or alkalinity. Which would be helpful. Can’t return now. Just wasted $400. I read reviews and was hopeful but I’m guessing all the good ones got this thing for free.