Abstract: A reef rack system for aquariums is provided, which includes a ledge supported by first and second removably attached posts having first and second lengths, respectively. The posts each include a first channel having a first width extending along the length of the post on a first side of the post and a second channel having the first width extending along the length of the post on a second side of the post opposite to the first side of the post. The posts also have a first plurality of protruding ridges along the length of the post on a third side of the post between the first and second channels and a second plurality of protruding ridges extending along the length of the post on a fourth side of the post between the first and second channels, the fourth side of the post being opposite to the third side of the post. The ledge includes a frame, a first attachment frame attached to the frame, and a second attachment frame.