I am new to Copper Power, and to copper in quarantine in general. I bought an API Copper test kit for this. I used the dosing instructions of this thread and arrived at about 11 mL for bringing 9 gallons up to 2.0 ppm. I tested with the API several times and I am coming up with just a faint yellow, no more than 1.0 ppm.
My next step is to go buy another kit, maybe Salifert and cross check. I don't want to add more copper without being sure the test kit is accurate. Expiration is 2020.
Any recommendations?