Started on my background tonight. This is for my 10 gallon setup for my Garter.
4x8 sheet of foam board $12.00ish
Can of spray foam $3.00
Bag of Eco Earth. Don't remember the price but it was cheap
I have enough foam board and Eco to do many backgrounds.
Made a couple "cliffs" as guides using sticks. I don't think this step is necessary now that I did it. You could just cut the foam as you please, but this is my first time so I'm learning as I go.
Covered the wet foam in Eco Earth. Threw more on the non covered spots as it expanded.
Let it expand and dry for an hour or so. Then tuned it up to dump the excess Eco
Cut the "cliffs" and dug out a little cave. Tomorrow I'll get some elmers glue and thin it and brush it on the white spots and reapply the Eco.