I have a 10gallon QT. I dosed copper power and the Hanna Checker says 1.87ppm. How much more do I need to add to get it to 2.5ppm? I already feel like I have added more than what the bottle says. The bottle says 1oz per 20 gallons. 1/2oz for a 10 gallon which is 3 teaspoons. I have done that plus 3/4 teaspoons. Im scared that I overdosed, however the checker doesn’t say that.