#drainage layer

No problem! I’d suggest shopping around and finding what the cheapest options are for you, as it may depend on what you can find locally or what you can get free shipping on, as well as the price of these products.

Drainage layer options:

Zoo Med Hydroballs

Exo Terra BioDrain

Hydroton Hydroponic Grow Rock

Growstone GS-1 Hydro Stones

LECA (lightweight expanded clay aggregate)

NEHerp LDL (lightweight drainage layer)

Josh’s Frogs False Bottom

TheBioDude Drainage Layer

Egg Crate

Gravel

Some of the hydroponics materials may be cheaper since they are not aimed at animal keepers.

If you absolutely can’t afford another drainage layer material, gravel is possible. You can use aquarium gravel. However, gravel is extremely heavy, and also doesn’t have capillary action which the other, porous drainage layers do.

Here is how to create a simple egg crate false bottom: (Page One, Two)

Here is a more complex build incorporating PVC pipe supports.

The reason they have that warning is because of the silica content. 

The same silica content that play sand has -- that is why play sand often has warnings on it that are the same! Yet we use play sand as a component in bioactive substrate and as substrate for hermit crabs, fish, and other animals. And people let their children play in it. That’s even what it’s sold for. (The warnings in California are even more dire!) All natural beach sand also contains silica and has the same risks.

Silicosis is very serious. It is a risk of any dusty material containing silica. Hydroton is an expanded clay product which also contains silica, and there is a risk in breathing the dust on it. 

Glass and clay are essentially variations on the same minerals. 

I work with ceramic material for a living, and we take many cautions in working with it. We never sweep, we only mop. We wear ventilators when handling dry clay. We never mix clay or glaze materials without using a huge filtering vent. We do not sand pieces except under the vent, wearing a mask. 

You should be very careful breathing things like dusty excavator clay, decomposed granite, pumice, diatomaceous earth, and similar products also. It is also in almost all dirt (this is what caused all the respiratory issues during the Dust Bowl).

Silicosis is accumulative and once you breathe in silica the damage is done. You can have acute silicosis from breathing a lot at once, but there is also chronic, which is breathing smaller amounts over time.

You should rinse both expanded glass drainage and LECA or Hydroton, but one is not safer than the other. It is best to wear a mask when doing so to avoid breathing the dust.

Once the product is thoroughly washed, they are both safe. They are also used in a way that keeps them wet, and below a substrate layer, meaning breathing dust is not a risk to the pet.

Aquarium gravel is also safe, but very heavy. A silica free choice that’s lighter is a false bottom using egg crate and fiberglass mesh.