Well his meter only reads to 1990 so he's going to have a hard time calibrating it to 2190.

If it's the basic meter i'm thinking of it reads at a 0.7 conversion scale and is calibrated by sticking it into "something with a known tds number" or what not and calibrated to that. I don't see anything on mine that switches to a 0.5 conversion and nothing in the instructions either so I'd be interesed to know if that actually works although I doubt I would change at this point because I'm really used to the 0.7 now.

Meters that read e.c should be calibrated with a conductivity solution instead of a tds solution (at 0.7 conversion I use 141.3 solution)