This SPECK Koi Gravel Medium is specially sized to support both biological and mechanical filtration in koi ponds and aquatic systems. The rounded gravel particles between 3‑5 mm form an ideal base layer under sand or other media, or can be used for gravel filters, bogs or plant substrate. Supplied in a 40 kg bag, this high‑quality washed and graded gravel ensures durability, reduced clogging, and enhanced water clarity, while being safe for fish and pond life.

• Key Features

• Grade: 3‑5 mm nominal size
• 40 kg bag – sufficient for medium‑sized pond’s filter media layer or gravel bed
• Washed and pre‑graded to remove dust and fines
• Rounded/pebble texture to allow good flow and reduce channeling
• Works well as support gravel under sand, or as a primary gravel filtration layer
• Fish‑safe and inert material; no coatings or additives

✓ Benefits

✓ Improves filter efficiency and water flow by preventing sand washout or clogging
✓ Enhances biological activity by providing surface area for beneficial bacteria colonisation
✓ Longer intervals between backwashing or cleaning
✓ Safe for aquatic life; non‑toxic and stable in pond environments
✓ Versatile use in filter support, gravel bed bio‑filters, or decorative pond substrate

Technical Specifications

• Particle Size: 3‑5 mm

• Bag Weight: 40 kg

• Typical Use: Support layer under sand, gravel filtration beds, bio‑filter zones

• Porosity & Drainage: High interstitial space to allow water flow and debris settling

• Usable Lifespan: Many years with occasional rinsing; replacement only when compacted or heavily fouled

What You Get

1 × 40 kg bag of SPECK Koi Gravel Medium (3‑5 mm size)