Bests & Worsts Reviews from Amazon

The description of this item claims "consistent results". Well, they're consistent all right. I tested my tap water, birdbath water, muddy ditch water, a bucket that put outside in the Fall with plants in it for Spring planting that I had added pesticide to because mosquitos were hatching, and I also tested coffee. Results were identical. How can that be? I'm returning it but since the package has been opened I'm not sure I'll get a refund.