Riare 10LBS Expanded Clay Balls Terrarium Substrate False Bottom Drainage Layer for Reptiles Review (2026)

What a false bottom drainage layer is for

Expanded clay, often called LECA for light expanded clay aggregate, is made by baking natural clay pellets until they puff up into a light, porous shape full of internal air pockets. In a bioactive terrarium or paludarium, a layer of these pellets sits at the very bottom of the enclosure, below the substrate and any barrier fabric, where it creates open space for excess water to drain into rather than pooling in the soil above. Riare describes its clay balls as 100 percent organic and pH neutral, which matters because anything added at the base of a bioactive build sits in long term contact with soil, plant roots, and the microfauna that keep the enclosure balanced. The honeycomb like structure inside each pellet also lets the layer absorb some moisture and release it gradually, which can help buffer humidity swings in an enclosure rather than only functioning as passive drainage.

Why the 10 pound bag suits bigger builds

Riare's pellets run in roughly the 4 to 16 millimeter range, a size that balances drainage speed against how much the layer compacts over time, and the 10 pound bag gives enough volume to cover the base of a larger bioactive enclosure without buying multiple smaller bags. That makes it a reasonable match for full size vivariums built for bigger reptiles, monitor enclosures, or paludariums, where a thin drainage layer would not hold enough excess water during misting or heavy watering. Smaller tanks built for dart frogs or single geckos generally need far less volume, so a 10 pound bag is more efficient for keepers setting up one large enclosure than for several small ones, where a smaller bag like a 4 quart size wastes less material overall.

Installing it correctly

A drainage layer only works as intended when it stays separated from the substrate above it, so Riare's clay balls need a mesh barrier, often landscape fabric or a similar material, laid on top before adding soil, moss, or any other substrate. Skipping that barrier lets fine substrate particles work down between the pellets over time, which gradually clogs the air pockets that make the layer effective and can eventually let soil settle directly against standing water. Rinsing the pellets before use is worth doing even though the bag is described as clean, since any dust from the baking and bagging process can cloud water sitting in the reservoir below. Once the barrier and substrate are in place, the drainage layer generally does not need to be disturbed again unless the enclosure is being completely rebuilt.

Storage and reuse

Because expanded clay is a bulky, low density material, a 10 pound bag takes up meaningfully more shelf or storage space than an equivalent weight of sand or gravel, which is worth planning for if the bag will not be used all at once. Riare packages it in a resealable foil pouch, which helps keep leftover pellets clean and dry between projects rather than leaving an open bag exposed to moisture or dust. The clay balls themselves are reusable, and keepers rebuilding an enclosure can typically rinse a drainage layer under running water and reuse it rather than replacing it outright, since expanded clay does not break down the way some organic substrates do over time. That durability is one of the main advantages of clay based drainage layers over materials that compress or decompose under sustained moisture.

Bottom line

Riare's 10 pound bag of expanded clay balls is a solid, reusable drainage layer for keepers setting up a larger bioactive reptile enclosure, and its pH neutral, organic pellets are sized appropriately for that scale of build. It is not the most efficient choice for a single small vivarium, where a smaller bag such as a 4 quart size wastes less material and stores more easily. Whichever size is chosen, the layer only works correctly with a barrier between it and the substrate above, so budgeting for that separately is part of getting real value from the bag.

Frequently asked questions