🪸 Launching soon · built by two reefers

Reef gear that actually fits.

Custom 3D-printed accessories for your reef tank — designed, printed, and tested in a real reef. Exact-fit. Reef-safe PETG. Shipped in days, not weeks.

What we make

Built for your exact tank.

No more zip-ties and compromises. Precision accessories modeled to the millimeter for the gear and tanks reefers actually run.

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Frag racks & coral placement

Standing and magnetic racks sized to standard frag plugs — sturdy, easy to clean, no wobble.

In testing
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Overflow & sump upgrades

Weir combs, strainer guards, and sump media baskets that fit your overflow precisely and run quiet.

Coming first
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Exact-fit AIO accessories

Media baskets, return nozzles, and mods cut for Waterbox, Red Sea, IM & more — to the exact chamber.

By tank model
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Equipment mounts

Clean brackets and holders for pumps, probes, dosers, and controllers — no adhesive, no clutter.

Custom builds
Why ReefDen

Designed by a reefer, not a spec sheet.

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Tested in a real reef

Every design is printed and proven in a live reef tank before it ever reaches you — fit, flow, and finish.

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Exact-fit, original designs

Modeled from real measurements for specific tanks and gear. Original work — built to fit, not to copy.

🛡️

Reef-safe PETG

Printed in durable, inert PETG that holds up in saltwater — no breakdown, no brittle cracking.

Shipped in days, not weeks

Made-to-order and out the door fast. Because you shouldn't wait a month for a $15 part.

Our story

Two reefers, five years, and a lot of broken gear.

ReefDen is two friends who met the way a lot of reefers do — geeking out over frags and bickering about alkalinity at the local fish store. Five years later, we've talked each other into (and out of) more tanks than we'll admit, traded a reef's worth of corals, and bailed each other out of every classic disaster: ich scares, a heater stuck "on," and the occasional 2 a.m. "why is everything closed up?!" panic text.

Between us we run two very different reefs and think in two very different ways — one of us lives in CAD and calipers, the other can't stop rescaping rock and chasing the next acro. Turns out that's the perfect team for building gear: one obsesses over the millimeter, the other over whether corals actually thrive on it.

ReefDen began with a wobbly frag rack and a $30 part that took three weeks to ship. We were sure we could make something that actually fit — so we did. Printed it, dropped it in the tank, watched it float (oops), fixed it, and printed it again. Every design still earns its place the same way: measured, modeled, printed, and reef-tested in our own tanks before it ever reaches yours.

Run your reef. We'll handle the gear.
"Two reefers who'd rather fix the problem than live with it."
5 yrsfriends in the hobby
2reef tanks (our test labs)
1caliper we fight over
frags traded & lost