so i just bought the 20-gallon marinefilter, and first, i had to trim down the extension tube because it was too long. but i have it in my tank now, and so the motor is a lot more noisy than my aquaclear. also, the flow-control valve doesn't do much. when you change it, it does not change how much water is put out. i am thinking of returning it and getting the aquaclear... any comments, suggestions, etc.?