For about three days in a row, I heard a slight 'beep' sound coming from my reef. It happened exactly every five minutes, but I could not find the source. I'd set a timer, then run into the fishroom and stand near whatever I figured was causing the sound, yet had no luck after several tries. Since I'd only get one tiny half-a-second to determine the source's origin, and when I couldn't would then have to wait five more minutes for it to happen once more, it became somewhat of a mystery. I wasn't about to spend all day trying to ascertain the object, though.