I recently added a bath and had the shower stall built out of stone. This is also a steam shower. I have found that after bathing, I leave the door open afterwards, there is a faint foul odor. My addition involved adding a second septic tank which I do not think is causing the smell. Anyway I have to use a strong cleaner, made for stone, to try and eliminate the smell and this is about three times a week. I am thinking the stone was not sealed properly which causes the smell but am not sure. Would appreciate some advise before calling in the stone folks to have them redo or reseal this shower.