Indeed. Pack of 50 0.380 blanks cost about £15.
Most airsoft stores sell them, and so do the place you buy the grenade from.
Little more expensive than the tornado, but much more durable.
Still need to clean it after each skirmish though. Takes about 5 mins.
9mm blanks are different so watch what you're buying. You need the ones with the lips i.e. 0.380 not 9mm. 9mm are for blank pistols, 0.380 blanks are for revolvers and the BFG