CaddyStack™ – Modular Filter Tower Extensions & Spare Parts

These CaddyStack™ Modular Filter Tower Extensions are individual replacement and expansion components designed to work with the CaddyStack™ Modular Filter Tower (Filter Sock Replacement Kit).

This product page is intended for reef keepers who already own a CaddyStack™ Starter Kit and want to:

• Replace a specific part

• Add more filtration stages

• Experiment with different media configurations

• BUILD YOUR OWN

👉 New to CaddyStack™?
If you don’t already own a Starter Kit, we strongly recommend starting here:
CaddyStack™ – Modular Filter Tower (Filter Sock Replacement Kit)
(Starter Kits include all core modules needed to build a complete system.)

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What These Parts Are For

CaddyStack™ Extensions allow you to customize and fine-tune filtration by adding or swapping individual modules instead of replacing your entire setup.

Each part twist-locks into existing CaddyStack™ towers and is fully compatible within its size category (2.75" / 4" / 7").

These are not standalone filtration systems on their own — they are modular building blocks for your existing CaddyStack™ platform.

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📏 CADDYSTACK™ EXTENSIONS – EXACT DIMENSIONS (READ BEFORE BUYING)

These are individual parts — NOT full kits.
All components are sized to match your existing CaddyStack™ system.

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🔹 2.75" CaddyStack™ Parts

Compatible System Diameter: ~2.5"

• Circle Mount: 2.56" diameter × 0.24" tall
• Short Tube: 2.48" diameter × 1.26" tall
• Short Cage: 2.48" diameter × 1.26" tall
• Tall Tube: 2.48" diameter × 3.19" tall
• Tall Cup: 2.48" diameter × 3.19" tall
• Tall Cage: 2.48" diameter × 3.19" tall

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🔹 4" CaddyStack™ Parts

Compatible System Diameter: ~4"

• Circle Mount: 4.04" diameter × 0.31" tall
• Short Tube: 3.46" diameter × 1.26" tall
• Short Cage: 3.46" diameter × 1.26" tall
• Tall Tube: 3.46" diameter × 3.31" tall
• Tall Cup: 3.46" diameter × 3.31" tall
• Tall Cage: 3.46" diameter × 3.31" tall

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🔹 7" CaddyStack™ Parts

Compatible System Diameter: ~7"

• Circle Mount: 7" diameter × 0.63" tall
• Short Tube: 6.30" diameter × 1.46" tall
• Tall Tube: 6.30" diameter × 3.19" tall
• Tall Cup: 6.30" diameter × 3.19" tall
• Tall Cage: 6.30" diameter × 3.19" tall

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⚠️ IMPORTANT

• These parts are NOT standalone systems
• You must already own a CaddyStack™ Starter Kit
• All parts only connect within the same size system (2.75" / 4" / 7")
• Mount must match your filter sock opening size

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CaddyStack™ – Modular Filter Tower Extensions & Spare Parts

These CaddyStack™ Modular Filter Tower Extensions are individual replacement and expansion components designed to work with the CaddyStack™ Modular Filter Tower (Filter Sock Replacement Kit).

This product page is for reef keepers who already own a CaddyStack™ system and want to:

• Replace a specific part
• Add more filtration stages
• Experiment with different media setups
• Build out additional towers

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👉 New to CaddyStack™?

If you don’t already own a Starter Kit, start here:

CaddyStack™ – Modular Filter Tower (Filter Sock Replacement Kit)

Starter Kits include everything needed to build a complete system.

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What These Parts Are For

CaddyStack™ Extensions allow you to customize and fine-tune your filtration without replacing your entire setup.

Each part:

• Twist-locks into existing towers
• Is fully compatible within its size category
• Lets you expand or modify your filtration anytime

These are modular building blocks, not full systems.

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Available Sizes

Spare parts are available in:

• 2.75"
• 4"
• 7"

All modules keep the same height system — only the diameter changes.

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Available Modular Components

Mounting Options

Circle Mount

• Designed for standard round filter sock openings (including WATERBOX)
• Common in most sump systems
• Drops directly in for even flow

Square Mount (2.75" Only)

• Designed for flat-edge AIO chambers
• Works with systems like:
  • UNS AIO
  • Landen
  • Hello Reef
• Dimensions: 2.5" × 2.5" × 2.75"

4" and 7" systems use circle mounts only.

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Short Modules (1" Tall)

Short Cage Module

• Open, high-flow design
• Ideal for quick mechanical filtration

Short Tube Module

• Solid sidewalls
• Forces water downward through media

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Tall Modules (3" Tall)

Tall Cage Module

• Open design for maximum flow
• Ideal for carbon, biomedia, or high-flow setups

Tall Tube Module

• Forces water through media for better contact time
• Great for layered filtration setups

Tall Cup Module

• Works like a traditional filter cup
• Drop in and fill with:
  • Filter floss
  • Pads
  • Carbon
  • GFO
  • Biomedia

To clean: replace media — no washing socks

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Why Buy Extensions Instead of Another Kit?

CaddyStack™ is built as a long-term filtration system, not a disposable one.

Extensions let you:

• Replace worn parts
• Expand for higher bioload tanks
• Fine-tune filtration over time
• Customize flow and media strategy

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Expandable by Design

Your system grows with your reef.

You can:

• Stack additional towers
• Mix and match modules
• Reconfigure anytime

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Reef-Safe & Built to Last

• Printed in reef-safe PETG
• No raw metal
• No exposed magnets
• Designed for long-term saltwater use
• Rigid construction that won’t collapse

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Important Notes

• These are extensions only
• A Starter Kit is required
• Media not included

Designed, manufactured, and shipped by Printed Reef