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:
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1× Short Cage Module (1")
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1× Short Tube Module (1")
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1× Mount (choose one):
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Circle Mount or
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Square Mount
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1× Tall Tube Module (3")
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1× Tall Cup Module (3")
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1× Tall Cage Module (3")
4” CaddyStack™ Starter Kit
Includes 6 total components:
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1× Short Cage Module (1")
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1× Short Tube Module (1")
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1× Circle Mount
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1× Tall Tube Module (3")
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1× Tall Cup Module (3")
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1× Tall Cage Module (3")
7” CaddyStack™ Starter Kit
Includes 5 total components:
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1× Short Tube Module (1")
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1× Circle Mount
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1× Tall Tube Module (3")
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1× Tall Cup Module (3")
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1× Tall Cage Module (3")
Why Replace Filter Socks with CaddyStack™?
Traditional filter socks:
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Clog fast
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Restrict flow
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Require frequent washing 👎
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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)
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Designed for filter floss or filter pads
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Ideal for fine mechanical filtration
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Easy to remove and replace
Tall Modules (3" Tall)
Available in three styles:
Cage Module
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Open, high-flow design
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Water can enter and exit from all sides
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Ideal for carbon, biomedia, or high-flow applications
Tube Module
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Solid sidewalls with bottom-only flow
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Forces water downward through media or floss
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Ideal for extending the height and forcing water deeper into the media
Cup Module
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Functions like a traditional filter cup
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Simply drop it into your sock holder or tray and fill with media
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Works with filter pads, filter floss, carbon, GFO, and biomedia
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To clean: replace media—no rinsing or washing socks
✅ CaddyStack™ Compatibility Guide (Based on Your Filter Sock Size)
⚠️ IMPORTANT:
CaddyStack™ requires a circular filter sock opening (like a standard drop-in filter sock).
If your tank only has a rectangular media basket slot, it will NOT fit unless modified.
🔹 2.75” CaddyStack™ Compatibility
Designed for nano/AIO systems with ~2.7–3” chamber width.
Likely Compatible (Rear Media Towers ~2.7–3” wide):
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UNS Dual AIO 30A
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UNS Dual AIO 60A
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Innovative Marine Fusion 10/15/20 (Square Mount)
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Innovative Marine Lagoon 25
⚠️If there is no circular drop-in opening, the Circle Mount will not fit — but the Square Mount may work in flat AIO chambers.
🔹 4” CaddyStack™ Compatibility
Requires a standard 4” round filter sock hole.
Based on your data, compatible with:
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Innovative Marine Fusion 30L / 40
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Planet Aquarium Tideline 31/49/65
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JBJ Nano Cube 28G
If your system uses a removable 4” filter sock, the 4” CaddyStack™ will fit.
🔹 7” CaddyStack™ Compatibility
Compatible with larger sump systems such as:
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CAD Lights SAIO 75G
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CAD Lights SAIO 100G
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Larger traditional sumps using 7” socks
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Red Sea sump systems (verify sock size — many are 4” class, not 7”)
Mounting Options Explained
Circle Mount
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Designed for traditional round filter sock cutouts
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Common in most sump systems
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Drops directly into the sock opening for even flow
Square Mount (2.75" Only)
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Designed for AIO rear chambers and flat-edge openings
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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:
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Add additional towers
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Swap modules
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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
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Made from reef-safe PETG
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No raw metal ever!
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No exposed magnets ever!!
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Designed for long-term saltwater use
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Rigid construction won’t collapse or deform
Ideal For
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Reef aquariums
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Nano tanks & AIO systems
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Sumps using filter socks
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Mechanical, chemical, and biological filtration
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Reef keepers who want less maintenance and more control
Why CaddyStack™ Over Other Media Towers?
Unlike fixed or single-piece filter towers, CaddyStack™ is:
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Fully modular
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Height-expandable
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Cross-compatible across sizes
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Supported by Printed Reef’s growing ecosystem of accessories
This isn’t a single-use product — it’s a filtration kit made easy.










