We have a lake like that here in CT. Try some glow. Chartruse, or reds. Put some meat on with your plastics we use spike (maggots). Recharge the jig often with an L.E.D. light. Are you useing electronics? The active crappie should rise offthe bottom in your case I'd work the 15'-25 ' depth. Recharge the glow often try some agressive jigging followded by long pauses, very long and hold absolutly still. With good electronics, you will know when to jig and when to pause by the reaction of the fish. When they are unresponsive, things can be slow, but you should be able to ice 12-15 on the slow nights and triple that on hgot ones. If all else fails, move over towards the bank and set up in that deeper water, but be NEAR the edge of the drop off. At the very least, you will be targeting active "crusining fish". The most important thing is to look for suspended fish or better yet, fish that will rise up to intercept your jig.