bio-active drainage layer

[akane]

Not as important in my desert tank which may not even need a drainage layer but I am starting a damper tank heavier on the compost for a Dekay's brown snake. I see almost everyone uses hydroballs plus a mesh cover. Is the separating cover necessary when they are under several inches of palm compost and sand plus leaf litter? Would crushed coral or crushed lava rock work just fine since I already have these things (would have to crush the lava rock smaller) and they will be so buried? It doesn't seem like the hydroballs would have as important of impact on the humidity compared to those planting straight into them and that I just need somewhere for excess water to settle out if necessary.

[eminart]

Some of the folks on the bio pages get a little silly with their drainage layers. They start breaking down capillary action of various substances and whatnot. It's really not rocket science. You just need an area with some voids that will let excess water drain downward. I use pea gravel. The only negative is that it's heavy.

As far as the mesh, you need something to keep the soil from combining with your drainage layer and filling all the voids. How you accomplish that is up to you.

[RAD House]

The point of a "drainage layer" is more than just for drainage. It also allows for bacteria to propagate that further regulate harmful waste like nitrogen. This is where traditional eggcrate type false bottoms fail. Hydroballs work best in my opinion because they allow these bacteria to grow and also it is relatively light weight compared to other rock layers.

[akane]

Lava rock and crushed coral are very porous. We use them in the aquariums because they grow a lot of bacteria and have a huge surface area.

[eminart]

The dirt above the drainage layer has all the surface area you need. But yeah, your rocks will work fine.