Blackwater diving is a different kind of night dive where you go several miles off shore and drift in the darkness.  Though you are relatively shallow, usually between 10 and 40 feet, the bottom is 400 + feet below so good buoyancy skills are a must.  While underwater you do not feel the effects of the Gulfstream currents that can carry you for miles during an hour long dive.  A myriad of planktonic and bizarre creatures migrate upward from the depths after dark, making each dive is a completely different experience.