Sand Went Black Under Decor...

[Harlequins]

I had a change around in my 16 gal cory tank and decided to replace the artificial stone decor with bogwood,and was surprised to find the sand had gone black underneath in a matter of a week! with a horrid smell of sulphur to go with it

The other one had flat bottom but not hollow was fine,but it seems that this stone decor with a hollow bottom which water went into but couldn't circulate hence turning my sand black.

 

[Louiseness]

I had a change around in my 16 gal cory tank and decided to replace the artificial stone decor with bogwood,and was surprised to find the sand had gone black underneath in a matter of a week! with a horrid smell of sulphur to go with it

The other one had flat bottom but not hollow was fine,but it seems that this stone decor with a hollow bottom which water went into but couldn't circulate hence turning my sand black.

I tend to find the opposite - under hollow pieces the sand is fine (presumably because the fish get under there) but under flat bottomed rocks I get discolouration.

Just stir it up, it'll go back to normal But I'm sure you know that )

 

[StandbySetting]

They're just small anaerobic pockets, nothing to worry about, just not very aesthetically pleasing!