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

CaddyStack™ is a fully modular filter sock replacement system designed for reef aquariums that use 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.

What’s Included in Each CaddyStack™ Starter Kit

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

2.75” CaddyStack™ Starter Kit

Includes 7 total components:

• 1× Short Cage Module (1")

• 1× Short Tube Module (1")

• 1× Mount (choose one):

  • Circle Mount or

  • Square Mount

• 1× Tall Tube Module (3")

• 1× Tall Cup Module (3")

• 1× Tall Cage Module (3")

4” CaddyStack™ Starter Kit

Includes 6 total components:

• 1× Short Cage Module (1")

• 1× Short Tube Module (1")

• 1× Circle Mount

• 1× Tall Tube Module (3")

• 1× Tall Cup Module (3")

• 1× Tall Cage Module (3")

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")

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

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 can enter and exit from all sides

• Ideal for carbon, biomedia, or high-flow applications

Tube Module

• Solid sidewalls with bottom-only flow

• Forces water downward through media or floss

• Ideal for extending the height and forcing water deeper into the media

Cup Module

• Functions like a traditional filter cup

• Simply drop it into your sock holder or tray and fill with media

• Works with filter pads, filter floss, carbon, GFO, and biomedia

• To clean: replace media—no rinsing or washing socks

Available Sizes & Fitment

2.75" Starter Kit

• Ideal for nano tanks, AIO systems, and rear chambers

• Two mounting options available:

Circle Mount

• Fits standard 2.75" filter sock cutouts

Square Mount

• Designed for flat-edge or rear AIO chambers

• Compatible with many AIO tanks including:

  • UNS AIO

  • Waterbox 10–25

  • Landen

  • Hello Reef

• Square Mount Dimensions:
  2.5" × 2.5" × 2.75" (L × W × H)

4" Starter Kit

• Designed for standard 4" filter sock chambers

• Ideal for medium reef systems and sumps

• Supports stacking multiple towers in taller chambers

• Uses circle mount only (standard sock cutout)

7" Starter Kit

• Built for large reef systems with 7" sock chambers

• Maximum media capacity and flow

• Uses circle mount only

• Optimized for high-bioload tanks

• Fully expandable with additional towers

Mounting Options Explained

Circle Mount

• Designed for traditional round filter sock cutouts

• Common in most sump systems

• Drops directly into the sock opening for even flow

Square Mount (2.75" Only)

• Designed for AIO rear chambers and flat-edge openings

• Square outer footprint with circular inner opening

Optional Modification

The inner hex grid of both mounts can be carefully trimmed with strong clippers if you prefer unrestricted flow or need additional clearance.

Expandable & Upgradeable System

CaddyStack™ grows with your reef.

You can:

• Add additional towers

• Swap modules

• Replace only the parts you want

Spare parts and expansion modules are available separately on the
👉 CaddyStack™ – Modular Filter Tower Extensions product page.

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 construction won’t collapse or deform

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

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 of accessories

This isn’t a single-use product — it’s a filtration kit made easy.