Ok my fiance and I are getting married ... I have a gorgous fish tank now, its white.... she wants to join the dark side of life and have an all black fish tank... the only part I havn't figure out is the rock... Can I even make black rock or paint white rock or something to that affect ... do they sell black cement ... please anything would be appracite don't feel like any idea is too stupid or already thought of I have a year so no rush on this build