Does anyone use a Aquaclear 50 for a 55 gallon. I bought the 50 for my new 55 gallon tank and was told by three stores to buy the fifty, so I did. Another store said if I use a fifty I will have to clean the tank three times a week. I asked another question on this board and they said a fifty was not enough I need more filtration. Please help I will return the 50 if it is not enough.