A coarse, highly aerated grade of highly porous agricultural volcanic tuff. Depending on the application, it also performs as a highly porous agricultural volcanic stone, engineered to increase air space, accelerate drainage, and improve structural stability in granular systems, aquaponics, coarse mixes, and long-life surface dressing.
The price shown is the retail price. Large-volume pricing varies by order size, packaging type, and destination.
This grade is the strongest option when root-zone air space, rapid drainage, and long-service granular applications are the top priorities.
All ratios are volumetric, not by weight. These are practical operating windows that can be adjusted according to crop, irrigation program, and water quality.
| Application | Recommended window | Technical reading |
|---|---|---|
| Granular-media hydroponics | 100% 10–25 mm after thorough washing | Works well with short, frequent irrigation cycles and ongoing monitoring of water and leachate quality. |
| Aquaponics | 100% washed 10–25 mm | An operating depth of roughly 25–30 cm is preferred in granular beds for most crops. |
| Increasing aeration within mixes | 15–30% in general mixes, with higher ratios in very humid environments or drought-tolerant crops | Blend it through the full volume rather than placing it as a separate bottom layer. |
| Succulent, bonsai, and cactus mixes | 40–70% depending on plant type and the base mix used | The greater the need for drainage and air, the higher the ratio can be raised. |
| Orchid mixes | 30–60% with bark or other suitable coarse components | Improves root-zone air and helps prevent prolonged saturation. |
| Surface dressing | Layer thickness 5–7.5 cm, and up to 10 cm in very dry sites | Leave a clear collar around the stem or trunk and avoid direct contact with the plant base. |
| Basal layer in deep containers | 1–2 cm only when needed to protect drain holes or add weight and stability | A practical use case only when the full medium has been designed correctly. |
Size selection remains tied to system design, medium depth, and irrigation or flood frequency.
10–25 mm excels when the goal is a highly aerated, fast-draining medium with a coarse porous surface that supports biofilms in granular beds.
This size serves aquaponics well after thorough washing, but performance depends not only on the raw material; bed design, flow pattern, and fine-particle control also matter.
Use it through the full medium volume to increase air and structure; placing it as a separate bottom layer is not the correct route to improve drainage.
This is one of the product’s strongest placements because it combines long service life, reduced evaporation, and an improved site appearance.
Condensed placements derived from the comprehensive technical guide and the approved mixing windows.
10–25 mm can be used as a full medium under very high irrigation control, or at roughly 20–30% within an organic base, because strawberry needs an aerated medium that does not dry too quickly.
This segment is one of the best uses for the coarse grade, with the ratio rising to 40–70% depending on plant type and the base mix used.
Use at 30–60% with bark or other suitable coarse materials, improving root-zone aeration and reducing long periods of saturation.
It is often used as a 5–7.5 cm surface dressing when needed, while the real technical work remains focused on improving the medium within the active rooting depth.
Core validation files, technical cards, and operating documents.
Yes, in granular media, aquaponics, and some coarse applications, provided it is washed well, irrigated with short frequent cycles, and monitored to avoid water stress.
No. Real drainage improvement comes from the composition of the entire medium; a bottom layer is limited to protecting drain holes or adding weight and stability when needed.
Yes. This is one of its strongest practical uses; the ratio can be increased in succulents and bonsai, and it performs well with bark and coarse components in orchid mixes.
It can be reused after removing roots and residues, followed by thorough washing and sanitization when needed between cycles.
Share the crop type, cultivation system, medium depth, and irrigation program, and we will guide you to the most suitable positioning between the fine grade, the coarse grade, or a blend of both.
