i personally wouldn't buy one of those, i just can't put out money like that for something that gives me a guesstimation, i can guess for free.....but on the same hand i'm not a professional fisherman either so what do i know.......i just tend to fish dark, opaque (black, junebug)colors when the water is really stained or dirty......and try to fish colors that are a little more natural (pumpkin, green pumpkin, watermelon seed) in clear water....and for stained water try naturals with a little chartruese ......pumpkin /chart is a great combo and usually a go to bait for me......also take into consideration the forage in the water you are fishing, type of cover (sparse cover= natural/ dense= attention grabber to draw them out), and barometric pressure (for some reason bass favor blue color variations on low pressure days) and sky brightness (bright sky= more translucent colors.......dark sky= opaque)
this is a very simple guide line.......it also just depends on your home waters.....the fish there could just like black all day, every day....who knows........good luck
SGT Christopher Johnson
US Army Presidential Salute Battery
NAFC Life Member