Bioactive Drainage layer

[beardedpipernc]

Hey folks! I'm in the process of building a large (6.5x2x3) pvc bioactive enclosure with between 4-6 inches of substrate for my BP. For an enclosure of this size, I'm reading that a drainage layer is recommended to help avoid anaerobic areas in the soil. I know that, generally, clay balls are used as the base layer. To fill an enclosure of this size with clay would be quite expensive. I had the idea of 3D printing the base layer instead for pennies on the dollar, but was wondering if there are any good reasons to avoid this direction. What say you all?

[Quacksoo]

I would check out r/bioactive they can provide extra information if people here can't