Thank you. I have a Taylor test kit...I think it is a k2006. I just got my pool up and running from having broken grids in my earth filter and blowing all the yuck back in. So all is good and chemicals levels are all good. The calcium was a little low but I read on here that vinyl pools don't need calcium. I would love to know how to help maintain my pool in the winter...I do have a mesh cover. Here in PA the pool is frozen pretty early in winter. Somehow I had bought into the thinking that more expensive bio guard had to be better at keeping my pool clean...shame on me. I have never had trouble keeping it clean in the summer but springtime is a nightmare.