Fluidized bed biological filter assembly for fish tanks

A portable fluidized bed biological filtration assembly for use with fish tanks, said filtration assembly comprising:

• a vertically oriented elongated tubular housing having a top end, a bottom end, a height H1, and a width W1;
• and a filtering chamber formed in said tubular housing;
• H1 is in the range of 6-24 inches and W1 is in the range of 2-6 inches;
• said tubular housing is made of plastic material;
• an upright oriented elongated upper inner tubular member having a width W2 that is less than W1, said upper inner tubular member being positioned within said tubular housing;
• said upper inner tubular member having a top end that forms a contaminated water inlet port and a bottom end that forms a vertically oriented water outlet port;
• a bottom cap having a tubular side wall that slopes downwardly and inwardly to form an inverted-cone shaped member;
• said bottom cap having a top end, and a bottom end having an inner surface;
• said top end of said bottom cap being secured to the bottom end of said tubular housing;
• a top cap secured to the top end of said tubular housing;
• said top cap having an inlet port for receiving contaminated water and an outlet port that allows filtered water to exit and means connecting said inlet port to the top end of said inner tubular member and connecting said outlet port to the top end of said filtering chamber of said tubular housing;
• means connected to the bottom end of said upper inner tubular member for taking contaminated water that is vertically exiting its bottom end and directing the contaminated water in a plurality of radial horizontal paths adjacent the inner surface of the bottom end of said bottom cap;
• said means connected to the bottom end of said upper inner tubular member comprising a lower inner tubular member for centering and supporting said upper inner tubular member, said lower inner tubular member has a top end and a bottom end, said top end being connected to the bottom end of said upper inner tubular member and said bottom end having plurality of radially extending slots adjacent its bottom end through which contaminated water can pass;
• said bottom end of said lower inner tubular member being connected to the bottom end of said bottom cap;
• and
• a preselected volume of particulate material placed in the filtering chamber of said tubular housing adjacent to and surrounding the bottom end of said upper inner tubular member, said particulate material having a size in the range of 50-300 microns.