There are a number of reasons why you may want to consider going bio-active with your current or future reptile or amphibian enclosures. Perhaps the main reason is that going bio-active creates a tiny ecosystem right there inside your tank, helping to create a food web that eliminates excess waste. The second most beneficial reason for going bio-active is the isopods and springtails provide a consistant, self-sustaining supply of nutritious, calcium rich food- essentially creating an endless buffet for your reptile. Finally, isopods come in a whole range of colors and sizes and eat a plethora of various foods, so you can include a rainbow of color morphs from a species that fits your needs to further enrich your enclosure. Many isopods are also considered pets in their own right, some exotic species being valued at over $50 per animal, and can add more creatures to love to your collection.
A bio-active set-up is an enclosure that has been colonized by beneficial bugs (isopods and springtails) that clean up mold, detritus, and feces. These bugs are isopods and springtails and they are natures' janitorial crews. They can be extremely useful for consuming left over fruits, vegetables, commercial reptile food, insect parts and shed skins. This prevents potentially toxic mold from taking over these unwanted remains and spreading to other parts of the enclosure where it could cause harm, disease or even death. This is especially important in humid enclosures like dart frog terrariums, and planted tanks.
For planted terrariums, add approximately 300 springtails and 20 adult isopods to a 10 gallon enclosure containing 2-3 inches of 1:1 soil to coconut coir substrate. Then add desired plants, being sure they are not toxic for your intended reptile. Many species appreciate having an enriched enviornment that includes a variety of hiding spots, textures, and colors. This can be accomplished by using different species of plants to acheive levels throughout the enclosure with ground cover, bush areas to hide in, and larger sturdier plants to climb on. Finally add exercise areas and additional hides. Most reptiles are shy creatures and will feel more secure in their enviroment if given an ample number of places where they can feel safe from exposure. These can include wood huts or branches, rocks, as well as commercial plastic options. Then give the isopods and springtails about 3-4 weeks to become fully established, having a sufficent number of eggs, juveniles and adults to ensure a consistantly preoducing population. Then you can consider the tank bio-active, and add your animals. If your tank is already inhabited, no worries, it just may take the cleaners a little longer to establish themselves as some will be consumed by the reptiles.
Add a layer of drainage material to the bottom of what is to be your land portion, it should be as deep as you intend your water depth to be. You can use a variety of materials like pumice, clay, or gravel. Cover with a mesh cloth. For lightweight materials like clay balls that float and can become unruly, mesh bags can be filled to keep them in place. Once your land area is established and covered in mesh, follow the same steps as above, beginning with adding 2-3 inches of substrate to the tank. When the tank has been planted and seeded with cleaner crews water can be added. Fill with water until it reaches the mesh layer, just below the soil. This provides a consistant moisture source to the plants that will wick up through the soil, without becoming overly wet. Cover the soil areas with moss to help maintain humidity and provide additional plant enrichment. The water should be oxygenated either with a bubbler, filter or waterfall effect to prevent becoming stagnant. For water deeper than 3 inches or containing fish a quality filter should be used.
Springtails primarily eat mold. They can live in substrate that is boggy and wet to barely moist. They thrive on food molds that create long fuzzy tendrils and wreak havoc on the health of tanks and feeder insects. In fact, springtails can be added to colonies of crickets and roaches that are kept on moist substrates to prevent spoiled food from wiping out a colony (sometimes overnight). Isopods feast on a number of various wastes like mold, decaying wood, detritis, and feces with some species preferring certain food sources over others. Given the right ratio of isopods : substrate level : creatures in enclosure, isopod cleaner crews can virtually eliminate the need to disassemble and completely sanitize reptile enclosures unless stricken by serious circumstances such as a mite infestation. Many planted bio-active terrariums need little more cleaning than a vigorous spraying of glass walls followed by a paper towel buffing.