Yes, these are not very good. While the Alkalinity, pH and Calcium Hardness seemed to work ok, the colors are too difficult to match and a given color can include a large range of readings, and give you no way to figure out what amount of chemical(s) would correctly balance your pool water.The Free and Total Chlorine squares are way off - told me I had absolutely none of either, whereas my regular pool test kit (as well as the local pool store) showed my chlorine levels to be in the correct range.Better to go with a standard liquid drops test kit, with demand reagents, so you know how much of whatever chemical to put in.I cannot recommend these for pool maintenance.