Aquarium media reactors and fluid beds are used to maintain water quality and to keep the water moving. Media reactors are used to remove impurities from the water and to keep the water moving. They are made of a porous material that allows water to flow through it. The water is then forced through a series of filters that remove the impurities.
Fluid beds are used to keep the water moving and to aerate the water. They are made of a material that is permeable to air and water. The water is forced through the material and the air is forced through the material. This aerates the water and keeps it moving so your aquarium stays clean and healthy.