Keeping your tank and its components healthy is made easier by the presence of API Marine Complete Trace. This all-natural reef supplement is so effective because it contains over 60 essential trace elements found in sea water. Add it to your marine environment and see the difference.Features: API MARINE COMPLETE TRACE is an all natural reef supplement containing over 60 essential trace elements found in sea water. This complete mixture of key trace elements plus iodine is an essential supplement for the reef or marine tank.