since I've been dry fly fishing most of my ff career, I'm pretty clueless when it comes to some nymphing techniques. today i was fishing a beadhead, and the thing wouldn't sink more than an inch below the surface. so I put some split shot about 8 inches up from the fly like someone told me to do and same thing, wouldn't sink. I was attempting to get this thing down deep into the pools. what should I do? add more split shot? where should the split shot be placed?