If you plan to use Glow-in-the-Dark bbs as tracers in low light conditions, make a mix of them and the bbs you normally use. That way you are not giving off a steady stream of glowing bbs that the opposing team can see and track where the shooter is shooting from. If 1 per 5 shots is the Glow-in-the-Dark kind, you will be able to see where the bbs are hitting and the enemy will (usually) not be able to see where the shots are coming from.