I just bought a rena filstar xp2 filter and i just wanna know from anybody who uses this filter if it's normal to hear a humming noise from the outlet spray bar(where the water comes out). Also when you put your hands or touch the outlet tube you could feel some vibration, which could probably be resulting the noise(which is starting to annoy me.....).....I read the instruction twice before i installed it and i know for sure that i installed it properly....Is this normal or did I buy a defective filter.....thanks.....