I'm having a few issues with these strips, including stripping squares (as others have noted) and weird separate ratings for kH and alkalinity (which should be the same but different scales and different have readings from the same tank). However, the biggest problem is the extremely inaccurate pH values. I have four different pH testing methods (digital pH meter, API batter kit and HGI test strips for my pool and this one). All my other methods have shown that my tank has a pH of 7.6 and these strips are 6.8! They consistently performed MUCH worse than all of my other tests and I nearly lost some very expensive fish as a result. I don't know how accurate other readings are, but kH and alkalinity are often very different. The alkalinity seems to agree with my HGI readings for kH, so I suspect it agrees more than the others. If you need to use stripes I suggest you stick with the API. They are more expensive and measure fewer parameters, but are much more accurate and measure almost everything you need.
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