triple monitor, 2 devices color adjusting

Hi,
I bought 3 korean 2056x1440 monitors which do not have an on screen display for adjusting colors. All adjusts must be done on the video card side..

Problem is I can't find a tool that will let me adjust the colors for all 3. The nvidia x server settings application displays "X Screen 0" and will only let me adjust 1 monitor.

I've tried googling but the other tools I've found I can barely understand. (dispcalGUI for example)

Just need a pointer to what tools/commands will let me adjust color temperatures for an individual monitor.

I have 1 newer graphics card, and the monitor attached to it is looking good for colors/etc. The older graphics card has 2 monitors attached and both just look absolutely horrible for colors.. I dont do gaming or anything so I can't justify buying a newer card just for color purposes..

Well, FWIW, I would NEVER purchase a display that did not have on-board color and other display controls. Caveat Emptor! They NEVER come the same out-of-the-box...