Red line turns to grey in water as far as the fishes eye sight goes and will not disappear all together,it might be a good line to use for feeder work as the line sits on the deck it will not stand out so much as mono would,i use fluorocarbon line more than anything in my fishing but then again i only target the local commercials from around my area.
A word of caution here if you don't mind,a few weeks ago the Angling Times paper gave away some RED EYE line(i think it was called)and i found out that the knot strength is very weak with this line,the knot in question is the standard half Blood Knot,it is useless and breaks so easy BUT if you use this line for feeder work and use knots like the grinner then it seems to hold up fine although some said they had problems with there feeder work with this line so it pays to really check this line out BEFORE use,i hope i have not bored you to death on this i do tend to go on anyway i hope it helps you out a little
