I added 6 inches of cheap fine play sand to one of the ends of the tank for my melanurus wrasse to play in, and to add a bit of biofilter. The sand looked brown under sun light but is a pleasant lunar-surface grey under the reef lights. I didn't do 6 inches over the entire tank because I wanted to preserve the visual impact of the tall rock work, and I like the look of the sand slope on the one side.
SUNLIGHT
REEF LIGHT
![](https://lh3.googleusercontent.com/3QMkLTcIwDVmLbmi41Yqtd92wnK0boI1SUmLx6oprYYd5YLYYCwbieNVZLvf2bI99atsWhon6MD9qpOev0Wml6_itZs2OcULLoMCifq-W3nJwIhoTv_k0qg0M0RqLix4AGANPUeG0CdTu5XjKpPbhRe9_jiT5dKWFTCN1MBKXP7uQ1KJxfjx_ei8mGkzlwhZxqB4yea4jj7t7-9ceYsp2-MhPggg0H8UfhENNpbIVu0_xcsO9TeHhy_EgCDYl78dpD8zItNGrd2Ry5Oq1uK265Ak91p__-vtkzfZi3XpCSNNuLSQy3eformj0WUQiO91Zy9YOALQp1ZbOedfyhoHbfGLYGBOFJwFFVeIIprrjNT8gH3ornndnYSXadT-hFK0D_zhLR7MrKFKDFRLhLYJj93Eb6GulG07u4DteTzARYY81qdzKbKETM-BrkcZtDjFBsNG8npQfXiOhxe_FZ-fmMoEsE1puLbeCiNYwDhG91xP_U5-Fqxf0n_UQ6uGcKxnSkssPQ6JdZruLT4LqitmDufV3iqyq1BcsJ4MMDx428ueF-MSRVTL1EuQjHSDf396yCbE55RK4fYFEBFjZ3f9s9UXfJeE2bVfnKHRvet2niJXO7JqhOt8m7lvvSn3mvcGRvBjOziIUQQYaW6FSPcykACywEGFUE01-kXL_T0z54pdGFIttGzPzVTKI65n=w876-h657-no)