Abstract:
A system for filtering and treating waste generated or collected in the water of a fish pond. The system includes a pump, pre-filter, piping, a valve assembly, and a filter media container enclosing a plurality of discrete filter media. The filter media are generally hollow, plastic structures with a plurality of external ribs and internal dividing walls having a high surface area-to-volume ratio and can support a high volumetric density of naturally occurring heterotrophic bacteria. The heterotrophic bacteria establish colonies on the internal and external surfaces of the filter media and biologically metabolize waste that is trapped on the media. The bacterial metabolization transforms much of the waste to an aesthetically and biologically neutral form thereby reducing the need for chemical treatment of the pond water. The system includes a backwashing mode to agitate and remove unreacted waste from the system and direct the waste stream out of the system.

Description:
RELATED APPLICATIONS 
     This application is a continuation application of U.S. application Ser. No. 10/242,059 filed on Sep. 10, 2002 which is a divisional application of U.S. Pat. No. 6,447,675 based on application Ser. No. 09/652,228 filed Aug. 29, 2000, entitled “Fish Pond Filter System.” 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to the field of ornamental landscaping and, in particular, to a filter system designed to efficiently remove solid wastes and biologically decompose suspended wastes in fish ponds. 
     2. Description of the Related Art 
     Fish ponds accumulate and generate a variety of contaminants and waste products that must be removed and treated to maintain the attractive appearance of the fish pond and the health of the fish living therein. The exposed water surface tends to retain air blown dust, dirt, and leaves and other plant matter that falls in. The fish themselves produce excrement that is a solid waste material and a source of unwanted biological activity. The temperate closed water ecosystem that is essential for the fish is also an excellent environment for the growth of algae and other undesirable living organisms. Fish food that remains uneaten by the fish can contaminate the pond and nourish undesirable living organisms. The closed system of a fish pond also favors chemical processes such as ammonia production that, if left unchecked, can rapidly degrade the appearance of the fish pond and its ability to support healthy fish. 
     The accepted method of maintaining the health and appearance of a fish pond is to separate the solid waste from the water, react the chemicals to either remove them or make them non-damaging, and treat the water to kill undesirable organisms. Two methods have typically been used to do this. One is to filter out the solid wastes and dispose of them, treat the water with a variety of chemicals and/or high intensity UV light to kill biological undesirables, and react the undesirable chemicals. The other is to employ a filter medium that retains the solid waste and decomposes the waste with biologically active bacteria that live on the filter medium. This method would also typically require treatment with high intensity UV light or chemicals to eliminate the undesirable biological and chemical constituents, although the chemical and/or UV light treatment regimen may not be as rigorous as with simple filtering. 
     A variety of methods and apparatuses are known to remove solid material from a liquid, however a major concern with removal of solid waste is what to do with the waste once it is separated from the water. Separation devices that depend on density differences, such as a centrifuge, are not effective in fish pond applications because many of the waste solids are approximately the same density as the water they are in, therefore the effective devices typically employ some type of filtering to trap the solids. The two major ways to handle the separated waste are to discard the waste trapped in a filter along with the filter or to backwash the filter and direct the waste stream elsewhere. A disadvantage of removing the waste trapped in a filter along with the filter is that generally these types of filters are a single use filter and thus must be replaced with a new one when the old one is full. It can be appreciated that the labor and cost to perform this replacement would be a drawback to a user for which the fish pond is a decorative and recreational item. 
     In order to avoid the cost and inconvenience of changing filter elements, the preferred method of removing trapped waste is to utilize some form of backwashing. Backwashing essentially consists of reversing the direction of water flow in the filter and thereby forcing the waste products out a waste outlet. The filter media does not typically need to be removed and after the backwashing is complete, the filter media is ready to retain more waste. Advantageously, fish ponds are often located adjacent garden areas and the backwashed water contains partially decomposed fish and vegetable waste that makes a beneficial fertilizer in the garden. However, the water discharged in the backwashing procedure is typically a cost to the user and minimizing water discharge is a concern particularly in areas where water is in limited supply. 
     The biological reaction process is an advantageous adjunct because the heterotrophic bacteria that perform the reaction are naturally occurring in the pond water. No user action is needed to establish and maintain a colony of beneficial bacteria other than to provide a place for them to live. Also, biological reaction converts many of the undesirable chemicals to non-harmful forms and thus reduces the need for chemical treatment. The chemicals used for chemical treatment are relatively expensive and many users would understandably like to minimize their handling of chemicals. The heterotrophic bacteria are not suited to live freely suspended in water and require a surface on which to grow. This has typically been done on the filter medium which generally consists of a gravel bed or filter mat. 
     A disadvantage to biological reaction is the relatively large amount of reactor volume and time typically required for the process to occur. With traditional gravel or filter mats, a biological filter/reactor can require a filter/reactor volume of up to 40% of the volume of the pond itself. It can be appreciated that such a large filter/reactor assembly is expensive to purchase and install and can negatively affect the aesthetics of the fish pond system. In addition a traditional biological reaction filter design can require several weeks to several months for the bacteria to substantially decompose the deposited wastes. The time required for waste decomposition must be such that the waste is decomposed at at least the rate it is deposited. Otherwise the filter becomes overloaded and can no longer protect the health and appearance of the pond. 
     As the bacteria live on a solid surface, there is an upper limit to how many can live on a given area, i.e. their population density. The time and volume required for a biological reaction filter can be dramatically reduced by providing increased area for the bacteria to live on and thereby increasing the number of bacteria resident in the filter reactor. The optimal filter media provides the highest surface area-to-volume ratio possible. With gravel or fibrous mats, the bacteria live on the surface and from a consideration of the shape of a piece of gravel or fiber it can be seen that other configurations of filter media would provide greater surface area for a given volume of media. 
     One type of filter media on the market with a higher surface area to volume ratio than gravel or fibers is the ACE-1400 media. The ACE-1400 media is made of plastic tubing with a specific gravity slightly less than one, which is cut to be slightly longer than the diameter of the tubing. The ACE-1400 is approximately 3.5 mm in diameter and 5 mm long. It can be appreciated that a hollow tube can support bacteria on both the outer and the inner surface. The size and shape of the hollow tube media is such that it has 15 to 20 times the surface area of an equivalent volume of gravel or fiber matting. 
     The ACE-1400 type media is typically placed in a container and pond water is pumped through the container so as to flow generally upwards. Since the ACE-1400 media has a specific gravity slightly less than one, the media floats towards the top of the container. Since the pond water is generally flowing upwards in the container, waterborne waste material is trapped throughout the media, but predominantly towards the bottom. The naturally occurring bacteria reside on and within the ACE-1400 media and digest the waste that lodges within the media. 
     The container is also provided with valves and piping to backwash the container periodically by reversing the water flow direction downwards and then out of the container. The backwashing causes the media to swirl and tumble, thereby releasing trapped solids. A properly sized container filled with the appropriate amount of media would generally require backwashing once a week. The container is provided with screens so that the media does not escape the container during either backwashing or normal operation. The filter system is also provided with screens to restrict larger solids such as leaves, twigs, and fish from being pumped into the filter container. 
     It can be appreciated that the more media that is in a filter system, the more surface area is provided for heterotrophic bacteria growth. However, because the ACE-1400 filter media is of a uniform size and shape, movement of the water tends to cause the filter elements to stack in a uniform manner, particularly when the container is filled to a relatively high percentage of capacity. The stacking process tends to create channels or voids in the filter media. These channels provide paths for the water to flow along without requiring that the water pass through the filter media. It can be appreciated that the filter is not effective in trapping and decomposing wastes if the water is not passing through the media. The stirring motion of backwashing randomizes the orientation of the filter elements, however they tend to re-stack and create channels in a relatively short time after the system returns to normal filtering flow. 
     While the ACE-1400 filter media and system offer advantages over traditional disposable filters and chemical treatment or gravel or fiber matting filter systems employing biological waste decomposition, it can be appreciated that improvements upon this system would be an advantage to the users of fish ponds. It can be appreciated that there is an ongoing need for a filter system for fish ponds that employs naturally occurring bacterial metabolization of wastes to remove these wastes from fish ponds. The system should be economical to purchase and install. The filter media should be reusable and provide the maximum surface area to volume ratio possible to support a maximum number of beneficial bacteria and to enable the system to be sized as small as possible and decompose the solid wastes as rapidly as possible. The system should require minimal use of chemicals to treat the water. The backwashing method should be as efficient as possible to remove the maximum amount of waste and extend the periods between backwashes, while avoiding channeling effects and corresponding failure to filter. 
     SUMMARY OF THE INVENTION 
     The aforementioned needs are satisfied by the fish pond filter system of the present invention, which in one aspect is a novel filter media with an increased surface area-to-volume ratio. In another aspect, the invention is a filter reactor with a more efficient backwashing system. 
     The extruded bio-tube filter media of the present invention is formed from extruded ABS plastic with a specific gravity slightly greater than one. The extruded bio-tube is generally tubular with internal and external ribbing. The addition of the internal and external ribbing provides approximately twice the surface area for the bio-tube of the present invention compared to a similar sized simple tube media, such as the ACE-1400. In addition, the internal ribbing provides smaller interior passages and allows the media to trap proportionally smaller waste material. 
     An additional advantageous feature of the present invention is that the media is provided in several different sizes. Also, the present invention is sized so as to be generally 1.3 times as long as it is in diameter. The differing sizes and the shape of the media of the present invention inhibit uniform stacking of the media material. Since the media cannot readily stack together in a uniform fashion, channeling of the material is also inhibited. 
     In another aspect of the invention, an efficient backwashing system is provided. The system includes jets adapted to create a vortex within the filter media container during the backwashing operation. The vortex created more efficiently dislodges accumulated waste material and directs the dislodged waste and carrier water out a waste pipe. The vortex created within the fish pond filter system of the present invention more completely cleans the filter media in a shorter time and requires less water to do so. Thus, the fish pond filter system saves time and money. These and other objects and advantages of the present invention will become more fully apparent from the following description taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an end view of a typical bio-tube of the present invention; 
     FIG. 2 is a side view of a typical bio-tube of the present invention; 
     FIG. 3 shows end and side views of three different sizes of bio-tubes of the present invention and their relative sizes; 
     FIG. 4 is an assembled, perspective view of the internal plumbing of a fish pond filter container assembly; 
     FIG. 5 is a close-up perspective view of the backwash jets and intake pipe assemblies of a fish pond filter system; 
     FIG. 6 is an exploded, cutaway, perspective view of the filter mode of the fish pond filter system; 
     FIG. 7 is an exploded, cutaway, perspective view of the backwash mode of the fish pond filter system; 
     FIG. 8 is a top view of a valve body and valve handle of the present invention showing the positions of the different operational modes of the valve body and filter system; 
     FIG. 9 is a side view of the assembled fish pond filter system; and 
     FIG. 10 shows a typical installation of the fish pond filter system. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Reference will now be made to the drawings, wherein like numerals refer to like parts throughout. A fish pond filter system  100  draws water from a fish pond  300 , filters and treats the water to remove waste  304 , and returns the water to the fish pond  300  as shown in FIG.  10 . The fish pond  300  of this embodiment is an open air, closed-system container of water. The fish pond  300  can be outside or placed within a building or other enclosed structure. The fish pond  300  includes a plurality of fish  302 . Fish  302  shall herein be understood to include fish, crawdads, mud puppies, frogs, turtles, shrimps, or any other vertebrate or invertebrate animals suited to live at least partially in an aquatic environment. The fish  302  generate waste  304 , which is at least in part at least semi-solid biological waste material. Waste  304  shall be herein understood to also include other material that finds its way into the fish pond  300  such as leaves, other vegetable matter, dirt, or insects. The fish pond filter system  100  also includes naturally occurring heterotrophic bacteria  310 . The heterotrophic bacteria  310  feed on the waste  304  typically found in a fish pond  300  and remove the waste  304  from the fish pond  300  in a manner that will be described in greater detail below. The fish pond filter system  100  comprises a pre-filter  306  as shown in FIG. 10 which is positioned and adapted to screen out larger waste  304  particles which are approximately larger than ⅛″ in a well known manner. 
     The fish pond filter system  100  comprises bio-tube  102  filter media as shown in FIGS. 1 and 2. The bio-tubes  102  provide a surface to support the growth of heterotrophic bacteria  310  in a manner which is well known in the art and will be better appreciated following a more detailed description of the structure of the bio-tubes  102  and the fish pond filter system  100 . The bio-tubes  102  also retain and subsequently release water-borne solid waste  304  materials which the fish pond filter system  100  passes over the bio-tubes  102  in a manner that will be described in greater detail below. The bio-tubes  102 , of this embodiment, are extruded from ABS plastic in a well known manner. The bio-tubes  102  are provided with a plurality of integral structures formed at the same time and which will be described in greater detail below. The bio-tubes  102  of this embodiment have a finished specific gravity slightly greater than one so as to be slightly non-buoyant in water. 
     The bio-tubes  102  structure comprises a ring wall  104 . The ring wall  104 , of this embodiment, is made of ABS plastic and is generally an elongate, hollow, open-ended cylinder approximately 0.300″ outside diameter, 0.250″ inner diameter, and 0.390″ in length. The ring wall  104  has a wall thickness of approximately 0.025″ and provides a growth surface for bacteria in a manner that will be described in greater detail below. The ring wall  104  has an inner surface  106  and an outer surface  110  coaxial with and opposite the inner surface  106 . 
     The structure of the bio-tubes  102  further comprises external ribs  112 . The external ribs  112  are made of the same ABS plastic material as the bio-tubes  102  and are generally elongate rectangles of approximately 0.018″×0.035″×0.390″. The external ribs  112  are extruded with the bio-tubes  102  such that a first side of the external ribs  112  is adjacent and materially continuous with the outer surface  110  of the ring wall  104 . The external ribs  112  are positioned such that the long axis of the external ribs  112  (0.390″) is coaxial with the long axis of the bio-tube  102 . In this embodiment,  18  external ribs  112  extend radially outward from the outer surface  110  of the ring wall  104  and are approximately equally spaced about the circumference of the ring wall  104  which in this embodiment is approximately every 20° of angle. The external ribs  112  provide additional surface area to support the growth of heterotrophic bacteria  310 . 
     The structure of the bio-tubes  102  also comprises divider walls  114 . In this embodiment, the divider walls  114  are three elongate rectangles approximately 0.018″×0.125″×0.390″ and are made from the same ABS plastic as the bio-tubes  104 . The divider walls  114  have a first edge  116  along a long edge (0.390″) and a second edge  120  opposite the first edge  116 . The divider walls  114  are positioned such that the first edges  116  of the divider walls  114  are adjacent and materially continuous with the inner surface  106  of the ring wall  104  and the second edge  120  of each divider wall  114  is adjacent and materially continuous with the second edge  120  of each of the other divider walls  114 . The divider walls  114  are further positioned so as to be approximately equally spaced radially outwards from the common second edges  120 , which in this embodiment is 120° of angle. The divider  114  walls also support growth of heterotrophic bacteria  310 . 
     It should be appreciated that the ring wall  104 , externals ribs  112 , and divider walls  114  are all structures of the bio-tube  102  and, in the preferred embodiment, are extruded at the same time and from the same ABS material. The bio-tube  102  with the structures described has a surface area available for bacterial  310  growth that is approximately twice the surface area of a simple hollow, open-ended cylinder of similar dimensions, but without the external ribs  112  and the divider walls  114 . It should be appreciated that the overall shape of the bio-tube  102  and the number, shape, and placement of the external ribs  112  and divider walls  114  can be varied by one skilled in the art from the configurations described in this preferred embodiment without detracting from the spirit of the disclosed invention. 
     The bio-tubes  102  also comprise a plurality of internal passages  122 . The internal passages  122  are the openings within the bio-tubes  102  defined by two adjacent divider walls  114  and the included arc of the inner surface  106  of the ring wall  104 . The inner passages  122  provide a restricted opening for the passage of water and block and hold solid waste  304  material that is larger than the dimensions of the inner passage  122 . In this embodiment, the inner passages  122  will block solid objects that are generally larger than 0.100″ in at least two orthogonal dimensions. The bio-tubes  102  with internal passages  122  block solid objects that are approximately one-third as large as simple hollow cylinders of comparable size. 
     FIG. 3 shows one embodiment of the present invention with three different sizes of bio-tubes  102 . The bio-tubes  102  as shown are generally cylinders and in this embodiment are approximately 0.180″ diameter by 0.234″ long, 0.240″ in diameter by 0.312″ long, and 0.300″ in diameter by 0.390″ long. The different sizes of bio-tubes  102  inhibits uniform stacking of the bio-tubes  102  during use in a manner which will be described in greater detail below. It should be appreciated that alternative shapes, sizes, and number of different sizes and/or shapes of bio-tubes  102  could be employed without detracting from the spirit of the present invention. 
     The fish pond filter system  100  also comprises a water flow controller  124  as shown in FIG.  4 . The water flow controller  124  comprises a valve body  130 . The valve body  130  is provided with internal structures to control water flow in a manner well understood by those skilled in the art. The water flow controller  124  also comprises a valve handle  126 , which is an elongate member, approximately 8″ in major dimension and made of a plastic material. A first end  128  of the valve handle  126  is rotatably affixed to a top end  154  of the valve body  130  such that rotation of the valve handle  126  induces the valve body  130  to freely permit or restrict water flow through an inlet pipe  132 , an outlet pipe  134 , a waste pipe  136 , and/or a stand pipe  146  all exiting from the valve body  130  in response to the positioning of the valve handle  126 . 
     The inlet pipe  132 , outlet pipe  134 , waste pipe  136 , and stand pipe  146  of this embodiment are elongate members, generally open cylinders in profile, and made of a PVC plastic material. The inlet pipe  132  receives untreated water from the fish pond  300 . The outlet pipe  134  directs water which has been treated and filtered by the fish pond filter system  100  in a manner which will be described in greater detail below back to the fish pond  300 . The waste pipe  136  directs water, which may contain waste material  304 , out of the fish pond filter system  100 . The stand pipe  146  directs water flow to and from a backwash jet assembly  170  and intake tube assembly  172  in a manner which will be described in greater detail below. 
     The water flow controller  124  also comprises a pressure gauge/sight glass  140 . A first end  141  of the pressure gauge/sight glass  140  is provided with standard ¼″ NPT and is therewith threaded into the valve body  130  in a well known manner. The pressure gauge/sight glass  140  is adapted to provide a visual indication of the water pressure within the valve body  130  in a well known manner. The pressure gauge/sight glass  140  is also adapted to provide a visual indication of the presence of water within the valve body  130 . The water pressure indicated by and the visual condition of the water seen in the pressure gauge/sight glass  140  serve as indicia for an operator to control the operation of the fish pond filter system  100  in a manner which will be described in greater detail below. 
     The water flow controller  124  also comprises an attachment flange  142 . The attachment flange  142  is generally circular and approximately 7″ in diameter. The attachment flange  142  is made of a plastic material and is adapted to attach the water flow controller  124  to a container  202 , as shown in FIG. 9, in a manner that will be described in greater detail below. 
     The water flow controller  124  also comprises a media screen  144 . The media screen  144  is generally a cylinder, open on a first end  150 , closed on a second end  152  and approximately 6″ in diameter and 4″ high. The media screen  144  is made of a plastic material and is provided with a plurality of openings  148 . The openings  148  are generally rectangular, through-going holes in the media screen  144  sized so as to block passage of the bio-tubes  102  through the media screen  144  yet to readily allow the passage of liquid water. The media screen  144  has a second end  152  opposite the first end  150 . A circular opening  160  is provided in the center of the second end  152  of the filter screen  144 . The opening  160  is sized to fit closely around the outer diameter of the stand pipe  146 , which, in this embodiment, is approximately 1½″ in diameter. 
     The first end  150  of the media screen  144  is placed adjacent a bottom end  156  of the valve body  130  opposite the top end  154 . The media screen  144  is positioned such that the opening  160  is aligned with the center of the bottom end  156  of the valve body  130 . The media screen  144  is attached to the bottom end  156  of the valve body  130  with a plurality of screws in a well known manner. A first end  164  of the stand pipe  146  is positioned through the opening  160  in the media screen  144  and further into contact with the valve body  130  so as to securely attach to the valve body  130  and the media screen  144  in a friction fit in a well known manner. 
     A second end  166  of the stand pipe  146  is connected to the backwash jet assembly  170  and the intake tube assembly  172  as shown in FIG.  4  and in a close-up view in FIG.  5 . The backwash jet assembly  170  of this embodiment comprises a manifold  174 . The manifold  174  is made of a PVC plastic material and is adapted to contain and direct water flow in a manner which will be described in greater detail below. The manifold  174  includes 12 ports  176 . The ports  176  are adapted to direct water flow and are part of and made of the same material as the manifold  174 . The ports  176  are generally circular structures of the manifold  174  which extend radially outward and are arranged in three levels  184   a-c . Each level  184   a-c  comprises four ports  176  positioned so as to be at the same distance along the major axis of the manifold  174  and to be approximately equally spaced about the circumference of the manifold  174  which is approximately a spacing of 90° of angle apart. 
     A top end  180  of the manifold  174  is provided with female threads in a well known manner. The second end  166  of the stand pipe  146  is provided with male threads in a well known manner such that the male threads of the stand pipe  146  mate with the female threads of the manifold  174 . The top end  180  of the manifold  174  and the second end  166  of the stand pipe  146  are threaded together to achieve the connection between the stand pipe  146  and the backwash jet assembly  170  and the intake pipe assembly  172 . In an alternative embodiment, the threading referred to above need not be present and the manifold  174  and the second end  166  of the stand pipe  146  are joined with a cementing process well known to those skilled in the art. 
     A first level  184   a  comprising four ports  176  is located approximately 1″ from the top end  180  of the manifold. A t-fitting  186  is connected to each port  176  by a cementing process well known in the art. The t-fittings  186  are plastic pipe structures adapted to direct the flow of water in two substantially orthogonal directions. The t-fittings  186  have three openings  188  for the passage of water. A first opening  188  of each t-fitting  186  is attached to a port  176  of the first level  184  of the manifold  174  with a known cementing process. A second opening  188  of each t-fitting  186  opposite the first opening  188  is connected to a first opening  188  of an elbow  190  with a known cementing process. 
     The elbows  190  are plastic pipe structures which are bent at approximately a 90° angle such that water that enters one opening  188  of the elbow exits a second opening  188  in a direction generally 90° from the direction it entered. Jet caps  192  are connected to the second opening  188  of each elbow  190  and to the third opening  188  of each t-fitting  186  using a known cementing process. The jet caps  192  are generally cylindrical, open on one end, and closed on the other end. The jet caps  192  are made of a PVC plastic material and are sized to conform closely to the openings  188  of the t-fittings  186  and the elbows  190 . The jet caps  192  are provided with a jet opening  194  in the closed end. The jet opening  194  is a through-going hole in the jet cap  192 . The jet opening  194  is sized to permit restricted flow of water such that water delivered under pressure to the inside of the jet caps  194  exits at a high velocity through the jet opening  194 . 
     The t-fittings  186  and elbows  190  are connected to each other and the manifold  174  such that the jet caps  192  fitted to the t-fittings  186  and the elbows  190  point generally tangentially in a clockwise or counterclockwise direction in the plane of the first level  184 . The t-fittings  186  and elbows  190  are further positioned such that the t-fittings  186  and elbows  190  point at an elevation or declination from the plane of the level  184   a  so as to have an elevation or declination of generally between 0° and ±45° from the plane of the level  184   a  and thereby the plane of the tangential clockwise or counterclockwise direction. Thus water that is supplied to the t-fittings  186  and elbows  190  is directed out of the jet openings  194  so as to spray out in a generally tangential manner but also in a slightly elevated or declined direction. This serves to create a vortical flow pattern for the backwashing in a manner that will be described in greater detail below. 
     The intake tube assembly  172  comprises a second  184   b  and third level  184   c  located approximately 3″ and 5″ from the top end  180  of the manifold  174  respectively. Each of the second and third levels  184  comprises four ports  176  as previously described with respect to the backwash jet assembly  170 . A first end of an intake tube  196  is attached to each of the ports  176  of the second and third levels  184  of the manifold  174  such that the intake tube assembly  172  comprises eight intake tubes  196 . The intake tubes  196  are generally hollow, cylindrical, elongate members, open on the first end, closed on a second end, and made of a plastic material. The intake tubes  196  are provided with a plurality of intake openings  198  positioned between the first and second ends. The intake openings  198  of this embodiment are through-going slits in the wall of the intake tubes  196  and are sized and positioned to inhibit the passage of the bio-tubes  102  yet to allow minimally impeded passage of liquid water. 
     The ports  176  of the second and third levels  184   b  and  184   c  are positioned such that the intake tubes  196  extend radially outward from the manifold  174 . The ports  176  are further positioned such that the intake tubes  196  of each of the second and third levels  184  are positioned approximately 90° apart about the circumference of the manifold  174  and such that the ports  176  of the second and third levels  184  are positioned approximately 45° from being in alignment with each other. Thus, the intake tubes  196  extend radially outward approximately every 45° about the circumference of the manifold  174  in two levels  184 . 
     The fish pond filter system  100  comprises a filter mode  200  as shown in FIG.  6 . It should understood that FIG. 6 is an exploded, cutaway perspective view of the fish pond filter system  100  with several components of the fish pond filter system  100  not shown for clarity. FIG. 6 shows an alternative embodiment of the intake tube assembly  172  wherein the intake tubes  196  are positioned so as to extend radially outward from the manifold  174  and so as to be positioned approximately every 45° about the circumference of the manifold  174  in a single level  184 . It should be appreciated by one skilled in the art that the operation of the intake tube assembly  172  as described as follows is substantially similar to the operation of the embodiment of the intake tube assembly  172  previously described. 
     The fish pond filter system  100  comprises a container  202 . The container  202  is a hollow, closed structure made of a plastic material. The container  202  is sized and adapted to hold approximately 15 to 150 liters of water. The container  202  is preferably sized to adequately filter the volume of the fish pond  300  in a manner well known to those skilled in the art. The container  202  comprises an opening  204  in a top end  206 . The opening  204  is a generally circular through-going hole in the top end  206  of the container  202  and is approximately 6″ in diameter. 
     The water flow controller  124  is partially inserted into the container  202  through the opening  204  such that the stand pipe  146 , the backwash assembly  170 , and the intake tube assembly  172  pass into the interior of the container  202 . An O-ring  210  is placed between the top end  206  of the container  202  and the valve body  130 . The O-ring  210  is generally a toroid approximately 6″ in overall diameter and ¼″ in cross-section and is made of a rubber material. The O-ring  210  inhibits water flow out of the container  202 . The attachment flange  142  is removably attached to the container  202  so as to secure the water flow controller  124  to the container  202  and also so as to hold the O-ring  210  between the container  202  and the water flow controller  124  in compression. The attachment of the attachment flange  142  in this embodiment comprises a clamping procedure well known in the art. In an alternative embodiment, the attachment of the attachment flange  142  comprises a threading procedure or other known methods of removably attaching two assemblies. 
     The container  202  also comprises a bottom end  220  opposite the top end  206 . The container  202  also comprises a drain hole  216  adjacent the bottom end  220 . The drain hole  216  is a through-going hole in the container  202  and is provided with internal, female threads. The container also comprises a drain plug  212  and gasket  214 . The drain plug  212  is a brass assembly provided with external, male threads and is sized and threaded so as to be removably threaded into the drain hole  216  so as to hold the gasket  214  between the container  202  and the drain plug  212  in a known manner. The drain plug  212  and gasket  214  inhibit water flow out of the container  202  when they are inserted into the container  202 . Removal of the drain plug  212  and gasket  214  allow water contained within the container  202  to freely flow out of the container  202 . 
     A plurality of bio-tubes  102  as previously described are inserted into the container  202  prior to the attachment of the water flow controller  124  previously described so as to fill the container  202  to approximately 50% of capacity. The filtering mode  200  comprises positioning the valve handle  126  to the filter mode  200  position such that water flows freely into the inlet pipe  132  and exits the bottom end  156  of the valve body  130  through the media screen  144 . The water fills the container  202  and exits the container  202  by passing into the intake tube assembly  172 , through the stand pipe  146 , through the valve body  130 , and out the outlet pipe  134 . 
     The water entering the fish pond filter system  100  typically is drawn from the fish pond  300  and includes waste  304 . The water enters at the top end  206  of the container  202  and exits adjacent the bottom end  220 . Thus, the water flow is generally downwards. The bio-tubes  102  have a specific gravity slightly greater than unity and thus will tend to sink and rest adjacent the bottom end  220  of the container  202  in the general manner shown in FIG. 6 thereby defining the filtering media for the system  100 . Thus waste  304  contained within the water will pass generally downwards and because of the configuration of the bio-tubes  102  as previously described, the waste  304  will be substantially trapped within and on the upper extent of the bio-tubes  102 . The differing shapes and sizes of the bio-tubes  102  are such that the flow of water within the container  202  and through the bio-tubes  102  induces the bio-tubes  102  to stack in a random manner and to not create channels or voids with the bio-tubes  102 . 
     The waste  304  trapped within and on the bio-tubes  102  serves as food material for heterotrophic bacteria  310 . The heterotrophic bacteria  310  are naturally occurring in the fish pond  300  and are carried into the fish pond filter system  100  during use. Over time, the heterotrophic bacteria  310  establish colonies on the surface of and within the bio-tubes  102 . The heterotrophic bacteria  310  metabolize the waste  304  that becomes trapped on and within the bio-tubes  102  and substantially transform the waste  304  into forms which are more aesthetically pleasing in the fish pond  300  and which are not harmful to the health of the fish  302  in a well known manner. For example, the heterotrophic bacteria  310  metabolize nitrogenous compounds such as ammonia. The structures of the bio-tubes  102  as previously described provide a greater surface area for the culturing of the heterotrophic bacteria  310  than other known filtering systems and can support a greater density of heterotrophic bacteria  310 . Thus, the fish pond filter system  100  can process a greater waste  304  load and/or at a faster rate than other comparably sized filtering systems. 
     The heterotrophic bacteria  310  are not capable of completely metabolizing all of the waste  304  that typically enters a fish pond  300  and this unreacted waste  304  will accumulate over time. Eventually the amount of unreacted waste  304  will accumulate to the point of restricting flow through the fish pond filter system  100 . This situation is indicated by the water pressure indicated by the pressure gauge/sight glass  140 . 
     The fish pond filter system  100  comprises a backwash mode  230  as shown in FIG.  7 . The backwash  230  mode is initiated by positioning the valve handle  126  to the backwash  230  mode position. This induces the valve body  130  to direct water flow from the inlet pipe  132 , through the valve body  130 , through the stand pipe  146 , and out through the intake tube assembly  172  and the backwash jet assembly  170  and into the container  202 . The water fills the container  202  if it is not already full and then flows past the media screen  144 , into the valve body  130 , and out the waste pipe  136 . 
     The water flow out of the intake tube assembly  172  dislodges waste  304  material that has accumulated on the intake tubes  196 . The water flow out of and the orientation of the backwash jet openings  194  induces a vortical or cyclonic flow  232  pattern within the container  202 . This vortical flow  232  causes the bio-tubes  102  to tumble and swirl, efficiently dislodging waste  304  trapped within or on the bio-tubes  102 . The vortical flow  232  further advantageously sweeps the dislodged waste  304  upwards and tends to cause the waste and its carrier water to segregate from the bio-tubes  102 . 
     The backwash  230  mode is conducted for a variable period depending on accumulated waste  304  load that, in this embodiment, is approximately 10 minutes. A user can consult the pressure within the valve body  130  and the visible condition of the water flowing therethrough as indicated by the pressure gauge/sight glass  140  as indicia for terminating the backwash  230  mode. 
     Advantageously, the vortical action results in the bio-tubes  102  and the accumulated waste  304  being entrained in the circling water so as to be urged upwards to the level of the waste pipe  136 . The configuration of the backwash ports  176  is such that the water is circulated at a higher velocity in the vortical or cyclonic fashion. The higher velocity of the water results in more of the waste matter  304  being entrained in an upward motion to the level of the waste pipe  136  (FIG. 4) thereby allowing for removal of the waste material  304 . Hence, the cyclonic motion of the water as a result of the placement and configuration of the backwash assembly  170  is better able to urge the waste material  304  into the waste pipe  136  for removal from the system  300 . 
     Moreover, the bio-tubes  102  are preferably selected so as to be heavier than the waste material  304  and preferably have a specific gravity selected so that the bio-tubes reside on the bottom  220  of the container  202  in the general manner illustrated in FIG.  6 . The waste material  304  generally collects near the upper surface of the layer of bio-tubes  102  comprising the filtration media and is thus located more proximal to the waste pipe  136 . Further, since the bio-tubes  102  are generally heavier than the waste material  304 , when the system  300  is being backwashed, the waste material  304  is generally entrained in the water above the bio-tubes  102 . This allows for flushing of the waste material  304  while reducing the loss of the bio-tubes  102  during the backwashing  230  process. 
     Following conclusion of the backwash  230  mode, the valve handle  126  is positioned to select a rinse  240  mode. In the rinse  240  mode, water enters the inlet pipe  132 , passes through the valve body  130  and enters the container  202  through the media screen  144 . The water then exits through the intake tube assembly  172 , the stand pipe  146  and out the waste pipe  136 . The rinse  240  mode settles the bio-tubes  102  in preparation for return to the filtering mode  200  previously described. 
     The fish pond filter system  100  further comprises a waste  250 , re-circulate  260 , and closed  270  modes selectable by positioning the valve handle  126  as shown in FIG.  8 . The waste  250  mode directs water flow into the inlet pipe  132 , through the valve body  130  and out the waste pipe  136 , bypassing the container  202  and filtering  200  process previously described. The waste  250  mode is used to lower the level of the fish pond  300  without filtering  200  the water. The re-circulate  260  mode directs water into the inlet pipe  132 , through the valve body  130 , and back out the outlet pipe  134 , bypassing the filtering  200  process previously described. The re-circulate  260  mode is used to circulate water in the fish pond  300  without running it through the filtering  200  process previously described. The closed  270  mode blocks water flow into the inlet pipe  132 . The closed  270  mode is used to shut off the fish-pond filter system  100  from the rest of the fish pond  300 . 
     A side view of a typical installation of the fish pond filter system is shown in FIGS. 9 and 10. The fish pond filter system  100  comprises a pump  320  as shown in FIG.  9 . The pump  320  is connected between the fish pond  300  and the inlet pipe  132  and is adapted to pump water from the fish pond  300  to the inlet pipe  132  when supplied with electrical or mechanical power in a well known manner. The pre-filter  306  screens out larger waste  304  particles such as leaves, sticks, or dead fish  302  which are approximately greater than ⅛″ in two dimensions that could damage the pump  320  or plug up the fish pond filter system  100 . In the embodiment shown in FIG. 10, the waste pipe  136  extends to discharge unreacted waste  304  and water in the backwash mode  230  as previously described. 
     The fishpond filter system  100  employs naturally occurring heterotrophic bacteria  310  as part of the filter mode  200 . The heterotrophic bacteria  310  metabolizes at least some of the biological waste  304  that is generated and accumulated in the fish pond  300  and thus reduces the chemical treatment that a user of the fish pond filter system  100  needs to employ to maintain the health and appearance of the fish pond  300 . Thus a user of the fish pond filter system  100  reduces the inconvenience and health risks associated with handling chemicals. 
     The bio-tubes  102  of the present invention provide a high surface area-to-volume ratio and thus can support an adequately large population of heterotrophic bacteria  310  in a relatively small container  202 . The shape and differing sizes of the bio-tubes  102  of the fish pond filter system  100  are configured to inhibit uniform stacking and channeling during the filter mode  200 . Other known filter media have a relatively low surface area-to-volume ratio and thus require larger, more obtrusive systems or are configured such that they tend to uniformly stack during filtering, which leads to the creation of channels within the filter media, which reduces the effectiveness of a filter system so equipped. By minimizing the size of the container  202  needed to adequately filter a given size of fish pond  300 , the fish pond filter system  100  minimizes the purchase cost, installation time and cost, and aesthetic impact of the fish pond filter system  100  while still efficiently and reliably filtering the fish pond water. 
     The fish pond filter system  100  also includes a backwash mode  230 , which creates a vortical flow pattern within the filter media container  202 . The vortical flow efficiently dislodges accumulated waste  304  trapped within the bio-tubes  102  and entrains the waste  304  out of the fish pond filter system  100 . The efficient backwash mode  230 , employing the vortical flow, takes less time to clean the filter media and directs less wastewater out of the system  100 . Thus, the fish pond filter system  100  furthers saves time and money for a user. 
     Although the preferred embodiments of the present invention have shown, described and pointed out the fundamental novel features of the invention as applied to those embodiments, it will be understood that various omissions, substitutions and changes in the form of the detail of the device illustrated may be made by those skilled in the art without departing from the spirit of the present invention. Consequently, the scope of the invention should not be limited to the foregoing description but is to be defined by the appended claims.