My experience has been that humpies will change preferences for color from day to day and in some cases over a few hours in the same hole. Pink is best to start with but I quickly change to chartreuse if I haven't drawn a bite in the first hour. If this doesn't change the bite situation I'll throw orange at them. Last resort is to switch back to pink but then test them with shades from pale to deep. I have no idea if river color, flow or light conditions is the cause of this behavior. Another of those mysteries of fishing.

Always FishOn!
Gooose