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

CaddyStack™ is a fully modular filter sock replacement system designed for reef aquariums that use 2", 2.75", 4", or 7" filter sock chambers. Unlike traditional filter socks that clog quickly, reduce flow, and require constant washing, CaddyStack™ replaces socks with a rigid, reusable, stackable filtration tower that gives you total control over mechanical, chemical, and biological filtration.

Designed, tested, and manufactured by Printed Reef, CaddyStack™ is built for reef keepers who want less maintenance, better flow, and long-term flexibility—without disposable socks.

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What’s Included in Each CaddyStack™ Starter Kit

To make it crystal clear, each CaddyStack™ Starter Kit includes the following components based on size:

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2" CaddyStack™ Starter Kit

Includes 6 total components:

• 1× Circle Mount
• 1× Short Cage Module
• 1× Short Tube Module
• 2× Tall Tube Modules
• 1× Tall Cage Module

Designed to work perfectly as a replacement for the
Red Sea 2" MAX NANO 225 Micron Thin Mesh Filter Sock/Bag
https://a.co/d/0a2tLLxD

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2.75” CaddyStack™ Starter Kit

Includes 6 total components:

• 1× Short Cage Module (1")
• 1× Short Tube Module (1")
• 1× Mount (choose one):
  • Circle Mount
  • Square Mount
  • Innovative Marine MidSize Rectangle Mount
  • 3" × 5" Rectangle Mount (Tideline AIO Lagoon Series)
• 1× Tall Tube Module (3")
• 1× Tall Cup Module (3")
• 1× Tall Cage Module (3")

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4” CaddyStack™ Starter Kit

Includes 6 total components:

• 1× Short Cage Module (1")
• 1× Short Tube Module (1")
• 1× Mount (choose one):
  • Circle Mount
  • Rectangle Mount (ESHOPPS)
  • NUVO™ SR60 | SR80 | SR120 Square Mount
• 1× Tall Tube Module (3")
• 1× Tall Cup Module (3")
• 1× Tall Cage Module (3")

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7” CaddyStack™ Starter Kit

Includes 5 total components:

• 1× Short Tube Module (1")
• 1× Circle Mount
• 1× Tall Tube Module (3")
• 1× Tall Cup Module (3")
• 1× Tall Cage Module (3")

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CADDYSTACK™ EXACT DIMENSIONS (READ BEFORE BUYING)

To avoid confusion — here are the exact physical dimensions of each size and every component.

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2" CaddyStack™ Starter Kit

Overall Assembled Size:

• Height: 8.25"
• Diameter: 2" class (58mm mount)

Individual Components:

• Circle Mount: 58mm diameter × 5mm tall
• Short Tube: 47mm diameter × 23mm tall
• Short Cage: 47mm diameter × 23mm tall
• Tall Tube: 47mm diameter × 58mm tall
• Tall Cage: 47mm diameter × 58mm tall

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2.75" CaddyStack™ Starter Kit

Overall Assembled Size:

• Height: 11.5"
• Diameter: 2.5"

Individual Components:

• Circle Mount: 2.56" diameter × 0.24" tall
• Square Mount: 2.5" x 2.5" x 2.75"
• Rectangle Mount: 3" × 5"
• 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

2.75” CaddyStack™ Innovative Marine MidSize Rectangle Mount Compatibility

The 2.75” CaddyStack™ is now available with an Innovative Marine MidSize Rectangle Mount designed to replace Innovative Marine’s MidSize molded filter sock with built-in hanger.

This molded sock measures approximately 5" × 3.25" × 10.5" and uses a built-in hanger that sits on the rim of specific Innovative Marine AIO tanks.

Compatible Innovative Marine tanks include:

NUVO Fusion 30L
Including Pro / Peninsula 30L variants with the same form factor

NUVO Fusion 40
Including Pro / Peninsula 40 variants with the same form factor

NUVO 30
Older generation, pre-Fusion

NUVO 38
Older generation

NUVO Lagoon 50

This mount allows the 2.75” CaddyStack™ system to replace the factory Innovative Marine MidSize molded filter sock and gives you a reusable, modular alternative instead of replacing the entire molded sock when it gets dirty.

Important Fitment Note:
Innovative Marine makes multiple molded sock sizes, including Nano, MidSize, and Large. Please verify your tank uses the MidSize molded filter sock before ordering this mount. Smaller Fusion tanks and larger IM systems may use a different sock size.

2.75” CaddyStack™ 3" × 5" Rectangle Mount Compatibility

The 2.75” CaddyStack™ is now available with a 3" × 5" Rectangle Mount designed for AIO aquariums that use a drop-in 3" × 5" rectangular filter sock.

Tideline AIO Lagoon Series
Also sold under multiple dealer brand names, including Aquarium Specialty, Nature Aquariums USA, South Seas Aquatics, and DFW Aquarium.

Compatible models:

• Tideline AIO 31G Lagoon
  
• Tideline AIO 47G Lagoon
  
• Tideline AIO 62G Lagoon
  

This mount allows the 2.75” CaddyStack™ system to replace the factory 3" × 5" rectangular filter sock in these AIO tanks.

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4" CaddyStack™ Starter Kit

Overall Assembled Size:

• Height: 11.5"
• Diameter: 4"

Individual Components:

• Circle Mount: 4.04" diameter × 0.31" tall
• Rectangle Mount: 7" length × 4.33" width × 0.98" 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™ Starter Kit

Overall Assembled Size:

• Height: 9.75"
• Diameter: 7"

Individual Components:

• 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 FITMENT NOTE (PLEASE READ)

These measurements are exact physical dimensions of the product.

Your filter sock opening must be:
Equal to or larger than the mount diameter

If your system is tight or slightly different:
You may need a custom mount

Pro Tip:

If you’re unsure:

• Measure your filter sock opening
• Or send us a photo + measurements

We’ll tell you exactly which size fits.

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Why Replace Filter Socks with CaddyStack™?

Traditional filter socks:

• Clog fast
• Restrict flow
• Require frequent washing
• Wear out and need replacement

CaddyStack™ solves these problems by using modular filtration towers that guide water through multiple stages of media inside a rigid, reef-safe structure that drops directly into your existing filter sock chamber.

• No washing socks
• No collapsing fabric
• No guessing what’s happening inside your filtration

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Fully Modular Filtration – Build It Your Way

Every CaddyStack™ system is made from interchangeable modules that twist-lock together, allowing you to build a filtration stack that matches your tank’s exact needs.

Short Modules (1" Tall)

• Designed for filter floss or filter pads
• Ideal for fine mechanical filtration
• Easy to remove and replace

Tall Modules (3" Tall)

Available in three styles:

Cage Module

• Open, high-flow design
• Water enters and exits from all sides
• Ideal for carbon, biomedia, or high-flow setups

Tube Module

• Solid sidewalls with bottom-only flow
• Forces water downward through media
• Ideal for directing flow deeper into filtration

Cup Module

• Functions like a traditional filter cup
• Drop in and fill with media
• Works with floss, pads, carbon, GFO, and biomedia
• Replace media — no washing required

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CaddyStack™ Compatibility Guide (Based on Your Filter Sock Size)

Important:
CaddyStack™ requires a circular filter sock opening.
If your tank only has a rectangular media basket slot, it will not fit unless modified.

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2" CaddyStack™ Compatibility

Designed to work perfectly as a replacement for the
Red Sea 2" MAX NANO 225 Micron Thin Mesh Filter Sock/Bag

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2.75” CaddyStack™ Compatibility

Designed for nano/AIO systems with ~2.7–3” chamber width.

Likely Compatible:

• Innovative Marine Fusion 10 / 15 / 20 (Square Mount)
• Innovative Marine Lagoon 25

If there is no circular drop-in opening, the Circle Mount will not fit — the Square Mount may work instead.

Innovative Marine MidSize Rectangle Mount (2.75" Only)
Designed to replace Innovative Marine’s MidSize molded filter sock with built-in hanger. This mount allows the 2.75” CaddyStack™ system to fit compatible Innovative Marine AIO tanks, including the NUVO Fusion 30L, Fusion 40, NUVO 30, NUVO 38, and Lagoon 50.

3" × 5" Rectangle Mount (2.75" Only)
Designed for AIO aquariums that use a drop-in 3" × 5" rectangular filter sock. This mount allows the 2.75” CaddyStack™ system to fit tanks such as the Tideline AIO Lagoon series and other matching 3" × 5" rectangular sock chambers.

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4” CaddyStack™ Compatibility

Requires a standard 4” round filter sock hole.

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4” CaddyStack™ Rectangle Mount Compatibility

Designed specifically for rectangular filter sock systems such as:
https://www.eshopps.com/product/rectangular-filter-sock/

Allows you to replace that sock with a full 4" CaddyStack™ system.

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4” CaddyStack™ NUVO™ SR60 | SR80 | SR120 Square Mount Compatibility

The 4” CaddyStack™ is now available with a NUVO™ SR60 | SR80 | SR120 Square Mount designed to replace the Innovative Marine NUVO™ SR60, SR80, and SR120 Replacement 4-Inch Sock Holder.

This mount allows the 4” CaddyStack™ system to replace the factory Innovative Marine 4-inch filter sock holder and gives you a reusable, modular alternative instead of constantly replacing or washing filter socks.

Compatible Innovative Marine tanks include:

NUVO™ SR60
NUVO™ SR80
NUVO™ SR120

This mount is designed specifically for the Innovative Marine NUVO™ SR-Series 4-inch square sock holder setup and allows you to run the full 4” CaddyStack™ modular filter tower system in place of the factory filter sock.

Important Fitment Note:
This mount is made for the Innovative Marine NUVO™ SR60, SR80, and SR120 4-inch sock holder. Please verify your tank uses the NUVO™ SR-Series 4-inch sock holder before ordering this mount.

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7” CaddyStack™ Compatibility

Compatible with larger sump systems such as:

• Larger traditional sumps using 7” socks

Note: Many Red Sea systems use 4" socks — verify before ordering.

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Mounting Options Explained

Circle Mount

• Designed for round filter sock openings
• Common in sump systems
• Drops directly into place

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Square Mount (2.75" Only)

• Designed for AIO rear chambers
• Square outer footprint with circular inner opening

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Innovative Marine MidSize Rectangle Mount (2.75" Only)

Designed to replace Innovative Marine’s MidSize molded filter sock with built-in hanger. This mount allows the 2.75” CaddyStack™ system to fit compatible Innovative Marine AIO tanks, including the NUVO Fusion 30L, Fusion 40, NUVO 30, NUVO 38, and Lagoon 50.

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3" × 5" Rectangle Mount (2.75" Only)

Designed for AIO aquariums that use a drop-in 3" × 5" rectangular filter sock. This mount allows the 2.75” CaddyStack™ system to fit tanks such as the Tideline AIO Lagoon series and other matching 3" × 5" rectangular sock chambers.

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ESHOPPS Rectangle Mount (4" Only)

• Designed for rectangular filter sock holders
• Compatible with:
  https://www.eshopps.com/product/rectangular-filter-sock/
• Allows you to run a 4" CaddyStack™ system in place of that sock

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Optional Modification

The inner hex grid can be trimmed if you want unrestricted flow or extra clearance.

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Expandable & Upgradeable System

CaddyStack™ grows with your reef.

You can:

• Add additional towers
• Swap modules
• Replace only the parts you want

Shop expansion parts here:
https://printedreef.com/products/caddystack-modular-filter-tower-extensions

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Reef-Safe & Built to Last

• Made from reef-safe PETG
• No raw metal ever
• No exposed magnets ever
• Designed for long-term saltwater use
• Rigid structure will not collapse or deform

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Ideal For

• Reef aquariums
• Nano tanks & AIO systems
• Sumps using filter socks
• Mechanical, chemical, and biological filtration
• Reef keepers who want less maintenance and more control

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Why CaddyStack™ Over Other Media Towers?

Unlike fixed or single-piece filter towers, CaddyStack™ is:

• Fully modular
• Height-expandable
• Cross-compatible across sizes
• Supported by Printed Reef’s growing ecosystem

This isn’t a single-use product — it’s a filtration system built to evolve with your tank.