Close up of Sand in Refugium..... AS said earlier I collected two different grain size sand......
Fine grain and white sand for DT, as it will give more bright look and will help for more reflection at the bottom of the tank and thicker grain for Sump..... because of less water flow in the chamber where DSB located I chose thick grain sand to let it oxygenate easily. Fine sand will cause to built up Sulphur problem.