Creaking tank

[Original Fin]

Whenever my heater turns on (set for 78) the tank creaks like on old barn door. I know this is just normal expansion/contraction from the temp differential, but should I be concerned about the noise, or do they all do that? My tank is about 7 weeks old. It's an all glass 55, with a glass tube heater, corner mounted. It didn't start off doing this, and it seems to be getting louder and more pronounced with time.

[Chameleon Bob]

I have an all glass 55 and it does not do that at all. Can you locate where on the tank it is coming from? Check level of tank might be crooked slightly and when it heats up it twits a bit. Strange though

[Original Fin]

I have an all glass 55 and it does not do that at all. Can you locate where on the tank it is coming from? Check level of tank might be crooked slightly and when it heats up it twits a bit. Strange though

I think I've found it. I have a hang on filter within 6" of the heater. It seems to be the plastic housing on the filter that's making the noise...I can live with that.