Saltwater Aquarium Substrate Information

Aquarium substrate is the material that covers the bottom of the tank and is as much a matter of aesthetic preference as biological advantage. Some aquarists use a bare bottom (BB) approach, which means they don't use any substrate.

  1. Coarse Crushed Gravel

    • Coarse crushed gravel is typically used in layers about 1 inch deep. It is not as common as it used to be because the larger size of the gravel allows detritus to drop between the spaces, reducing the positive biological impact of substrate.

    Medium Grain Substrate

    • Medium grain substrate is implemented in a fairly thin layer, usually of 1 to 2 inches. This provides the biological advantage of the substrate without the aesthetic drawback of some other substrate types.

    Live Sand

    • Live sand is sand harvested from the ocean. Its benefit and drawback are that it includes the live organisms that were harvested along with the sand.

    Deep Sand Bed

    • A deep sand bed is a thick layer of sand, usually between 2 and 6 inches deep. Theoretically, the thick sand encourages biological processes deep within the sand.

    Plenum System

    • A plenum system is a porous platform with sand on top. This creates space between the sand and the bottom of the tank where nutrients can sink without building up nitrates.