Tank making a cracking sound.

[Rob Labonte]

so, every now and then. at least once or twice a day that i hear, my tank makes a cracking sound. not to loud but still, its a bit annoying.

the first few times i heard heard it, i freaked out thinking that my tank was about to burst at the seams. but i seems to do it all the time and everything seems ok. but why is it doing this? has anyone else had this experience b4?

the only thing I can think that might be causing this is that the tank rests on a metal stand and im thinking it the metal stand expanding and contracting from temperature variances in the house??

im thinking of taking the tank off the tank and laying some foam strip between the stand and tank. but its a lot of work on a 120g tank to do if this is not the cause.

opinions greatly appreciated.

[Quatro]

I've heard something like that before.  I thought it was cichlids moving the gravel around (spitting it at the glass).  In your case, maybe the turtles scratching the glass.

[Rob Labonte]

nope def not. ive heard that sound before. thats  more like a minor squeeking sound.

this is a fairly loud cracking sound.

[White Lightning]

IS it salt or fresh? If it's salt it coudl be a mantis shrimp.

[Bees]

I notice some cracking when the lights come on or go out as the fixture heats up or cools off.  Any chance it is that or is there anything else that would intermittently heat and cool?  You mentioned your stand but is your house seriously drafty enough for that???

[Funkmotor]

+1 to White Lightning.  Could be a mantis or a pistol shrimp.  Actually, most likely it's one of those.

[Rob Labonte]

bees....you could be right about lights. i do use heat spot lamps that are on a 12/12 cycle.

so it could be the heat of those.

and its nothing in the tank making noise. its the tank. its freshwater with turtles. and im 100% shure its not them. ill be watching them when you hear the noise.