I would trust the Hanna tester over the API kit in every instance. Here is a trick though: mix up exactly five gallons of seawater. Add 7.4 milliliters of copper power to that and mix well. That should read 2.5 ppm copper. You can then use that water to do a partial on your QT, just so it isn’t wasted.I’m treating 2 tomato clowns in a qt. using Copper Power. Suspected ich. I had been using the API copper test kit, but the results were coming up in the yellow family, whereas the chart is more in the orange family. Based on hue, I estimated copper to be at about 2.0. I was gradually increasing copper in an attempt to reach 2.50 ppm. I just bought the Hanna H1702 copper tester and it is showing 4.70 ppm. That’s very high. Has anyone experienced this? Does anyone know if the Hanna tester shows inaccurately high ppm levels?
Jay