Hanna HR Copper Checker vs. Copper Power dosage instructions

[Obriy]

Copper Power dosage says "one fluid ounce for each 20 gallon of water which comes to about 13.3 ml for 9 gallon of water in my QT. When using it first time, I added 10 ml and added another 3.3 ml next day. Hanna checker showed 1.85 ppm after the first dose and 2.43 ppm after the second one.

I've recently set up my QT the second time for three firefish. Next morning after first 10 ml dose of Copper Power, Hanna showed 1.69 ppm. I added 3.7 ml more and checked with Hanna next morning that the copper level was at 2.27 ppm even though I'd added 13.7 ml in total, which should be over 2.5 ppm according to the dosage instructions.
Should I go with the checker and add a bit more Copper Power to reach 2.5 ppm readings, or should I stay with Copper Power dosing instructions?

 

[Jay Hemdal]

Personally, I’ve been targeting 2.25 ppm for both copper power and coppersafe. Unless there is an active infection, then I go for 2.5 ppm. Coppersafe, dosed to their instructions, is 2.25 ppm, I haven’t tested copper power recently, but I think it’s about the same. Remember, there can be some variation in testing with the Hanna tester. Just because it gives two decimal points, doesn’t mean it is always consistent.