Why are you using it? Generally you should avoid using chemicals whenever possible. What color is the water? What are your water stats (ammonia, nitrite, nitrate)? How did you cycle the tank, how long has it been set up?
I don't know how bclear works, but if it's meant to remove dust stirred up in new gravel, it won't remove a bacterial or algae bloom. If it'll remove either of those, it also poses a risk of killing off important beneficial bacteria.
