I am fairly new to fly fishing and had a question regarding nymph fishing. I know how to set up some different nymph rigs fairly well but I am unsure how much they should be weighted or how much split shot should be added to give them the ideal presentation. Do you want the split shot constantly banging off rocks on the bottom with the flies trailing behind or do you want is suspended off the bottom? Also, how do you know you are getting down deep enough if you can't spot your flies in the water? The only way I can really tell is if you are occasionally hanging up and then you know you are making contact with the bottom. Basically, if anyone could tell me how I would know if the nymph rig was properly weight it would be appreciated. Thanks.