So I have looked at tutorials for chaining pokemon on youtube and such but I have a question. This pertains to diamond since it has the poke radar. Why do you reset the poke radar? After you defeat a pokemon that is in your chain, you see more grass pieces shaking. Not always are they in a safe spot but they still shake. I don't understand why I'm supposed to reactivate the poke radar at 40 pokemon. Whats the point of resetting it and why do it at 40 and not at 4 or 400 pokemon?