I purchased a hob aquaclear 70 filter for my 20 gallon tank on amazon. It arrived today. I did what you normally do with filter, I lightly washed the sponge and activated carbon and placed it in the filter in the correct place. I placed it in my tank and filled it up with water and then plugged it in. I have been waiting for 6 minutes and the filter is not filtering nor flowing. The motor is slightly hot. I have looked up on this site other instances of failing ac 70 filters but haven't found an answer. Please help !