Self Sustaining Vivarium?

[DonLisk]

Here is a link to creating a false bottom with eggcrate, and the setup was for WTFs.

as for changing out substrate, if it drains properly and never picks up mites, or other unwanted inhabitants, then the substrate may never have to be changed, nut..... WTFs are pretty abusive to a tank and depending on the amount of animals and how often you remove visible waste/dropping will be the deciding factor here.
My RETF tank has not had the substrate changed in almost two years, smells nice, and the plants grow well without need for anything other than routine trimming of overgrowth.

Hope the link helps.
http://www.frogforum.net/vivarium-te...se-bottom.html