I use Poret foam as the only source of filtration in quarantine tanks, temporary aquariums, outdoor stock tanks and Matten Filters. I buy it usually in the form of 6x6x19-inch cartridges that come pre-drilled for an airlift. It can be cut down to shorter lenghts for smaller tanks or used full-length for stock tanks, etc. Glue a 6-inch ceramic tile to the bottom with silicone, insert a PVC tube of the correct size (I usually jam a 1-1/4-inch tube down there) and drop in an airstone, or of course you could use a powerhead. The PVC is swiss-cheesed with drilled holes to allow water to enter along the entire length of the sponge filter. As each hole is drilled, angle the drill upwards toward the center, so that bubbles don't find their way out of the tube and exit the top of the foam (I hate that! 
). An elbow at the top creates a more directed current than a straight bubble-up tube. I clean these filters usually once a week or so, but they can go much, much longer than that if you wish. You can powerspray the bejesus out of them (if you are on a well or other non-chlorinated source), squeeze them out until the water runs off clear...and they still retain enough beneficial bacteria to continue functioning beautifully.
I also use Poret as the initial mechanical filtration in my 360gallon sump-equipped tank. I have two one-square-foot sheets of 2-inch foam in series, 20ppi on top and 30ppi beneath. Top sheet is cleaned every day or two when I am home, while the bottom sheet is cleaned perhaps once a month. The top sheet may also go a couple or three weeks without a cleaning if I am working remote from home, but I like to remove the debris as often as possible when I can to prevent its breakdown by bacteria. Easiest way to remove nitrates is to limit how fast they appear in the first place. It takes seconds to powerspray these sheets in the yard during winter, or clean them in the tub during colder weather.
I have one particular sheet which is at least three years old, and has been powersprayed and vigorously squeezed out probably in excess of 500 times. It is still in perfect shape. No other foam I have tried even approaches this durability. Poret filters, if run off a central air pump/system, are the least expensive, most cost-efficient filtration I have ever tried.
). An elbow at the top creates a more directed current than a straight bubble-up tube. I clean these filters usually once a week or so, but they can go much, much longer than that if you wish. You can powerspray the bejesus out of them (if you are on a well or other non-chlorinated source), squeeze them out until the water runs off clear...and they still retain enough beneficial bacteria to continue functioning beautifully.I also use Poret as the initial mechanical filtration in my 360gallon sump-equipped tank. I have two one-square-foot sheets of 2-inch foam in series, 20ppi on top and 30ppi beneath. Top sheet is cleaned every day or two when I am home, while the bottom sheet is cleaned perhaps once a month. The top sheet may also go a couple or three weeks without a cleaning if I am working remote from home, but I like to remove the debris as often as possible when I can to prevent its breakdown by bacteria. Easiest way to remove nitrates is to limit how fast they appear in the first place. It takes seconds to powerspray these sheets in the yard during winter, or clean them in the tub during colder weather.
I have one particular sheet which is at least three years old, and has been powersprayed and vigorously squeezed out probably in excess of 500 times. It is still in perfect shape. No other foam I have tried even approaches this durability. Poret filters, if run off a central air pump/system, are the least expensive, most cost-efficient filtration I have ever tried.
