porous gyroid filter 3d model

Create a highly porous biological pond filter media optimized for 3D printing and bacterial colonization. Organic gyroid/coral hybrid structure with extremely high surface area, dense internal lattice, multidirectional water flow channels, rough FDM texture intentionally preserved for biofilm growth. Cylindrical and spherical modules, 50–80 mm size, printable without supports, max overhang 45°, wall thickness minimum 2.5 mm, strong enough for long-term submerged outdoor use. Open external cage structure combined with dense internal gyroid network. Water must circulate deeply inside the object while trapping oxygen-rich turbulence zones. Designed for koi pond and goldfish biological filtration. Functional mechanical realism, watertight printable STL, clean topology, no impossible geometry, optimized for 0.4 mm nozzle, PLA+ compatible, realistic industrial biomimetic design inspired by coral, lava rock and Japanese bio-media. High-detail engineering object, not concept art.