Goes between your drainage layer and your soil. That's it. But it's the part everyone skips and then regrets.

Here's the deal: without it, your substrate slowly sifts down into your clay balls. The gaps fill with mud, water stops draining, and a few months later the bottom of your tank is a swamp. Now you're tearing the whole thing down.

This stops that. Fine particles stay up top, the drainage layer stays open, water flushes through clean. Done.

Need a size that's not listed? Send your dimensions and we'll cut it for you.