I think I would downsize my jig, if I were considering continuing to use "vertical jigging" as the method of choice. If light taps were the types of bites I was getting, while using minnows, I'd think that the fish were not in a agressive mood ... but, were just being "tempted" by the "easy meal" factor. The slower fall, of a lighter jig, can be a tempting factor, as well. The murky water could also be stressing the fish, and be a reason for the light hits.
You could also try adding scent, or Crappie Nibbles, to your jig ... in order to give them cause to hold onto the jig longer, giving you a second or two longer to react to the bite (and set the hook). It would also increase the ability of the fish to "find" your offering, in those murky water conditions.
You might also try casting a jig to them. This creates a "reaction bite", which is usually more easily detected. Anytime, while casting a jig, you see the line jump or go slack ... that's a hit, and you need to set the hook immediately. You don't wait to "feel" the hit, you just want to "see" it !! Those "tics" or "thumps" or "jerks", in your line ... the line moving off sideways to the way it should be coming back towards you ... or sudden slack line (when you know your jig isn't on bottom) ... are all indications of a Crappie hit. Set the hook, after any of these line movements occur
You could, also, tip your jig with a minnow (in lieu of scents or Nibbles) ... and jig it or cast it.
Also understand that Crappie hits, on a moving jig, are usually only "one & done" ... while multiple, rapid fire types of hits, are usually Sunfish. They can be Bass, but they normally just inhale the jig and swim off with it. And it "can" be White Bass (Sandies) or even Yellow Bass, as they do sometimes nip & nibble at the bait. Hybrids, not so much :p ... as you probably already know ... they tend to use the "slash & dash" feeding method.
You might also be interested in trying what I call "Vertical Casting" : Crappie.com - Crappie Fishing Information and Adventure - Vertical Casting
... luck2ya ... & Welcome to Crappie.com
... cp