Biological Sponge Filters are a great addition to any tank. We use sponge filters in all of our tanks under 100 gallons as the only filtration; plus we use them in our larger tanks instead of using air stones. Any time we need a sponge filter all we have to do is pull one out of a tank and instant cycle; and if the main filtration should fail the sponges help to avoid the tank crashing. New Lower Pricing! Size Options: Up to 10 gallon - perfect for breeding tanks, bettas and other smaller fish that do best in a low current. Up to 25 gallon - make excellent additions to a breeding tank Up to 50 gallon - great economical filter Up to 60 gallon - With its tall and slender shape these filters take up much less floor space and work great in a column shaped tank Up to 80 gallon - features a wider and taller lift tube to increase the movement of water through the filter as well as creating current in the tank itself Up to 130 gallon - this filter is a beast. We use one in our 55 gallon rearing tanks when overcrowded and in our 125 gallon for added bacterial colonization.