I bought a 2ppm standard from Hanna, and the reader comes back at 1.95ppm, so as far as I can tell the checker is correct.I am having your exact same problem. Dosed 1.18ml/gal for 16 gal and got 1.67ppm with a brand new Hanna checker that arrived 7 days later after the dosing. I run a HOB filter with Marineland Rite-Size Ready-To-Use Filter Cartridges.
Copper Power must be selling a diluted product now or had an error in production. Good thing we have test kits!
