They had never tested the high range model. They tested the low range model, I don't know exactly what caused them to determine the low range model was not accurate in the presence of seawater. The low range model measures in PPB instead of PPM. So wouldn't be a suitable range for us anyway.
I have no idea what the intended use for the tester in freshwater would be, as my assumption would be possibly someone who may treat ponds and such. Copper is widely used as an algecide in local ponds etc. Also as mentioned above possibly any water treatment facility.
Neither here nor there, @Hanna Instruments is testing this product currently for our type of use. Patiently we wait. I have done everything I can to make it fail, yet to find a way...
I use the low range a few times with ei dosing to see if i need to modify my dosing of plantex csm+b. The other ingredients are so hard to test for, that copper gives a good indicator knowing the composition of what i am adding and inducing the concentrations present of things like iron or manganese.
No idea if this is what it was meant for, but what i use it for lol.