I've heard they're different gph outputs but never seen anything to suggest it or back up what I've heard..if you have a good drill bit set see what is largest size you can get in the sprayer hole. im still trying to find the site that listed the inner diameter difference as related to color. some have tried them and didnt like the pattern or lack of.
If I understood how that would effect the setup, then I would be estatic over that info. But I have no idea how it would change anything... I'll figure it out in a sec...ok, found it. this is what i found. they use red, green and blue to readily identify flow rate and orifice size.
blue=.04" orifice, flow of 7.5-11gph,
green=.06" orifice, flow of 15-21.8gph
red=. 075" orifice, flow of 21.7-31.4gph
flow rate depends on psi range of 10-20