4" Round Grey Airstone — Compact Hydroponic Airstone

4" Round Grey Airstone — Compact Elemental Airstone for Hydro & Aquarium

A smaller 4" round airstone — delivers the punch of oxygen that plants and fish need for impressive yields. Compact form factor makes this right for propagation reservoirs, smaller DWC buckets, or individual plant systems where a 6" stone would be oversized. Connects to any air pump using 4mm or 6mm airline tubing.

Why growers choose the 4" round airstone:

• Compact 4" form factor — fits small reservoirs, propagation cups, individual DWC buckets
• Fine bubble production — oxygen exchange happens at bubble surfaces, fine = more surface area
• Increases dissolved oxygen — healthy oxygenation for plant roots in hydro setups
• Fits standard air pump tubing — 4mm/6mm airline universal compatibility
• Right-sized for small setups — no point running a 6" stone in a 20L reservoir
• Reduces pythium risk — oxygen-rich water resists root disease
• Multi-purpose — hydroponics, aquariums, ponds all benefit

Who it's not for:

For larger reservoirs (50L+), a 6" airstone's larger surface area oxygenates more effectively. Match to your air pump output — too many stones per pump weakens bubble output from each. Clean every 4-6 weeks with a bleach soak to prevent mineral-buildup clogging. If bubble rate drops noticeably, it's cleaning or replacement time.

In stock now — ships same working day from our Staffordshire warehouse with free UK delivery over £100. Pick up in-store at our Stone shop (ST15 0SR) if you're local, or click & collect at checkout.