If you really must go for a 'bioactive' enclosure, first you should really understand what you're doing (I'm a qualified biologist, I specialised in ecology, even I would find it a somewhat challenging task, and certainly it would be a lot of work to set up and you'd need to closely monitor it). And secondly, choose an appropriate species. You'll generally do best with something which lives in a swampy/jungle/riparian environment. These things are going to cope best with the moisture. Ball Pythons are extremely tough things and might be able to cope, but only because they're tough enough to possibly be able to survive in the wrong conditions, as opposed to something which likes those conditions.
The concept is really cool, but it's not easy or practical, and generally not at all safe.
In nature, there is a deep ground full of dirt full of worms, beetle larvae, etc etc. The rain washes the nutrients into the soil and/or into waterways. Beetle larvae, worms etc eat the waste and take it underground. Flying insects eat it and fly away. Insectivorous animals eat these invertebrates and distribute the nutrients to completely different parts of the ecosystem. You just can't replicate that huge, complex environment in a little box with a couple of cm of dirt on the bottom. Attempting to generally turns out very much like forcing a snake to live in a toilet which you don't bother to flush.
Maybe start out with a moisture-loving species (probably not a snake as most 'wet' snakes are fairly sensitive, unless you want to go for an actual aquatic snake, some of which are much easier) and while sticking to keeping it clean, have a go at growing live plants in there. You'll still probably quickly give up because it's really difficult to make it work, but it's safer and easier.
