So my next challenge, what to do for a background?
I was originally going to go with something stone, but I decided to go with coco fiber.
Again I start with egg crate, this time I just used white Great Stuff because it was available in a larger can (and was cheaper

)
I picked some nice wood (that will later serve as a waterfall spot) and I also added a pipe for wires and tubes. After laying them out on the eggcrate, time to foam away.
I bought some coco fiber from a local pet store, which breaks apart easily after soaked in water. When it dried a bit, i covered the hardened foam with silicon and spread it on top.
I had a little problem with this method as some spots didn't hold very well
I'll wait until it dries and add some silicon where the foam shows through and reapply some more coco fiber... any other suggestions out there?
All said and done, the background fit in nice (aside from the touchup work that needs to be done)
And soon the tank will be planted...