The sections of the nearest rivers to me (Grand, Welland) are never really clear especially in the spring. I plan to do some crappie fishing this weekend and have tied some PT, and prince nymphs and some mini buggers in brown, black, olive, and chartreuse.
Any advise on which flies and colours would be best to use?
Thanks
Chartreuse is always a winner. Try Al Campbell’s Crappie Candy pattern here on FAOL. And under a VOSI, vertically oriented strike indicator (bobber) they can be especially deadly.
As Robin mentioned, chartreuse is good, but don’t overlook black for stained water.
Steve
I agree with the above. When I can’t decide which to try (black or chartreuse), I find a bicolor usually fits the bill. Try a black fly (mini bugger, for example) with a small “neck” or “butt” section of chartreuse.
In fact, just today during lunch I was fly-fishing in the light rain, and the pond was stirred up. I used a fly on a size 8 hook that I had tied on a tail of peacock herl, body of the same herl, and a “head” of chartreuse marabou wound on tight. I caught 3 bluegills and a decent bass! 
Good luck!
Or try both on a tandem rig!
I often fish large, black woolly buggars in discoloured flows, upstream, dead drift beneath an indicator like a nymph. Works a treat, and throws out a good silouhette.
chris