Dried sea cucumber.
Fish, shrimps.
Description Fluid Systems Gravel and water filter pebble is composed of sub-angular, hard, durable, and dense grains of predominately siliceous material. Extracted from a clean glacial deposit, Fluid Systems Minerals Gravel and Pebbleâ??s physical properties make it among the finest available in the world for water filtration applications. Fluid Systems water filter gravel is washed, kiln dried, and screened to meet exact in g specifications with strict adherence to quality control. Sand and gravel make good water filters because they form permeable layers. When comparing the rate of flow between different filters, it is generally found that the tighter the spaces in the filter, the slower the flow of water. These small spaces cause tiny dirt particles to be trapped in the filter media.
