Vivariums are used to home geckos, salamanders, turtles and frogs. They are designed to mimic the animal's natural habitat, both for the benefit of the animal and for an aesthetic effect. The background of a vivarium can look like rocks, trees or an assortment of foliage. It all depends on your personal taste. These backgrounds can be purchased premade, which can save a step for those who are not artistically inclined or don't want to spend time making their own. Vivarium backgrounds are painted with nontoxic acrylic paint and then sealed to protect the paint from water.
Wash off the styrofoam background with a dab of dish soap an a scrubby sponge. Rinse thoroughly to get rid of any soap residue.
Mix your sanded grout until it has the consistency of pancake batter. Line the sides of the styrofoam background with painter's tape or masking tape.
Apply the grout to the front of the styrofoam with the foam brush. Let it dry until it is hard and has set. Put on two more layers of grout, waiting between applications for the grout to set. On the last layer, make the surface of the grout as even as possible, filling in any holes or valleys that the first two layers may have created. Dab the brush along the surface to create a textured look. Let this sit for 3 days so that it is dry and the grout has set.
Remove the tape. If any grout got onto the edges, scrape it off with a paint stick.
Take brown acrylic paint and thin it with water. Brush it onto the grout surface. Start to make layers of three different earth tones, mixing the colours to create a camouflage pattern until the background is covered and has a natural look to it.
When you are done painting, spray nontoxic acrylic sealant onto the surface, bottom and sides of the background. Allow it to dry. Repeat this process two more times to finish your background. Let it sit for a week in a ventilated area before placing it in your vivarium.