What will happen if i use a external filter that is for a 92 to 144 us gal tank and 1200L/H and my tank is 58 gal i just connected it without the fish in tank and was thinking of getting a few 4in fish the guy at aquarium said that it is good my water will be clearer and then my friend told me that it will blow the fish away in the water so i stuck my hand in the water and it was o.k what do you think.[/b]