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.

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" 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

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")

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
- Trigger Oval 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")

CADDYSTACK™ EXACT DIMENSIONS (READ BEFORE BUYING)

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

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

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.

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

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

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.

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 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

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.

2" CaddyStack™ Compatibility

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

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.

4” CaddyStack™ Compatibility

Requires a standard 4” round filter sock hole.

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.

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.

4” CaddyStack™ Trigger Oval Mount Compatibility

The 4” CaddyStack™ is also available with a Trigger Oval Mount, shaped to drop straight into the oval filter sock opening used on Trigger Systems sumps.

It fits any Trigger sump with a 4” filter sock oval opening — the mount matches that oval, so the tower sits down in the holder the same way the factory sock does, with no adapters and no modification.

Important Fitment Note:
This mount is made only for the oval 4” sock opening. If your Trigger sump uses a round 4” hole instead, order the Circle Mount. Look down into the sock holder before ordering — the opening is either a circle or an oval, and that is the whole decision.

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.

Mounting Options Explained

Circle Mount

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

Square Mount (2.75" Only)

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

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.

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

NUVO™ SR60 | SR80 | SR120 Square Mount (4" Only)

Replaces the factory Innovative Marine NUVO™ SR-Series 4-inch sock holder
Fits the NUVO™ SR60, SR80 and SR120

Trigger Oval Mount (4" Only)

Shaped to the oval filter sock opening on Trigger Systems sumps
Fits any Trigger sump with a 4” filter sock oval opening
Drops in where the sock sat — no adapters, no modification
Not for round 4” sock holes — those take the Circle Mount

Optional Modification

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

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

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

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

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