Octo CR-3000 / 5000 Calcium Reactor Lid O-ring
SKU: ROP-CR-3-5-ORING
- 100% Genuine OEM Factory Gasket: Manufactured directly by Reef Octopus as an exact structural fit to drop into the specialized 7-inch threaded main lid groove.
- Premium Flexible Silicone Compound: Forged from a highly resilient, saltwater-safe silicone elastomer that resists compression setting and flat-spotting.
- Acid-Resistant Engineering: Built to maintain an uncompromised structural seal under non-stop exposure to highly acidic (6.5 to 6.8 pH) CO2-saturated fluids.
- Universal High-Capacity Fitment: Shared factory replacement footprint across the entire CR3000, CR3000D, CR5000, and CR5000D heavy-duty reactor lines.
- Leak-Free Siphon Lockdown: Ensures the primary reaction chamber can safely hold structural backpressure without dripping or losing gaseous carbon dioxide.
Reef Octopus
Globally trusted for premium protein skimmers and pumps, engineered in-house for unmatched reef filtration performance.
Reef Octopus CR3000 / CR5000 Replacement Calcium Reactor Lid O-Ring (SKU: ROP-CR-3-5-ORING)
The Reef Octopus CR3000 / CR5000 Replacement Calcium Reactor Lid O-Ring (SKU: ROP-CR-3-5-ORING) is an authentic, structural OEM sealing hardware component distributed by CoralVue to preserve high-pressure gas containment and prevent aggressive salt creep. High-capacity calcium reactors function by constantly recirculating a pool of aquarium water injected with carbon dioxide (CO2) across a massive bed of aragonite coral media. To lower the internal pH enough to dissolve the media, the entire system must maintain a strict airtight siphon. Because these commercial-scale 7-inch red lids are unthreaded and broken down frequently during media changes, the sealing gasket handles constant compression and friction. Over years of operation, standard gaskets will stretch, develop flat spots, or flatten out—leading to sudden pressure drops or trace water leaks inside your cabinet.
Molded from premium, chemical-inert silicone rubber, the ROP-CR-3-5-ORING forms an airtight, elastic barrier inside the pre-carved track of the heavy Super Reef Octopus (SRO) and VarioS 7-Inch Cylinder lid arrays. This replacement ring is explicitly calibrated to span both the standard single-tower and dual-tower (D) system layout scales. Replacing a compromised, dried-out, or salt-crusted gasket with this genuine factory piece keeps your internal pH levels perfectly stable, protects against low-pressure gas drop-offs, and shields your electronic equipment from destructive, fine salt spray.
Key Features
Prevents Corrosive Sump Closet Salt Creep: Re-establishes a flawless watertight lock at the highest pressure point of the cylinder, keeping dry filtration areas protected.
Maintains Airtight Internal pH Environments: Prevents gaseous carbon dioxide from bleeding out into the room, stabilizing your media dissolution loop.
Instant Friction-Fit Drop Installation: Form-fitted to slip directly into the integrated under-lid tracking tracks without requiring sticky sealing adhesives.
(Note: This retail box includes (1) individual silicone lid o-ring. Replacement 7-inch red threaded lids, clear acrylic reactor columns, pH probe holders, and VarioS DC recirculation pumps are sold under separate product categories).
Reef Octopus Reactor Lid O-Ring Map
| Gasket Profile Classification | Material SKU Identifier | Sump Cylinder Cap Scale | Target Reactor Platform Alignment |
|---|---|---|---|
| CR100/140 System O-Ring | Contact for Parts | Compact Metric Tracking | Classic CR100 (4") and Classic CR140 (5.5") |
| CR3000/5000 System O-Ring | ROP-CR-3-5-ORING | 7-Inch Heavy Dynamic Rim | SRO-CR3000(D), SRO-CR5000(D), VarioS CR3000(D) |
| CR7000 Large Scale O-Ring | ROP-CR-7-ORING | Commercial High-Volume Track | SRO-CR7000 Commercial Media Cylinder |
What’s Included:
(1) Reef Octopus High-Resilience Silicone Replacement Lid O-Ring
Technical Specs:
Official Manufacturing Title: Reef Octopus SRO Calcium Reactor Lid Oring (CR3000/CR5000)
SKU / Factory Part Identifier: ROP-CR-3-5-ORING
Structural Material Foundation: Low-Durometer Marine Saltwater-Grade Flexible Silicone Elastomer
Target Lid Geometry Sizing: Form-Fitted for 7-Inch Red Threaded Main Chamber Lids
Primary System Pathway Track: Reactor Cap Fluid Containment and Gas Vacuum Pressure Seal
Platform Series Compatibility: Reef Octopus CR3000, CR3000D, CR5000, and CR5000D (First Chamber Primary Cap Only)
WARRANTY
CoralVue, Inc. hereby guarantee this product to be free from defects in material and workmanship for a period of:
- 90days
Warranty is activated on the date of purchase.
This Standard Limited Warranty applies and is limited as follows:
- To the product only as long as it remains in the possession of the original purchaser.
- To the product that has not been subject to accident, misuse, or abuse.
- To the product that has not been modified, altered, defaced, or had repairs made or attempted by other than CoralVue, Inc.
- That CoralVue be immediately notified in writing within ten (10) days of the owner's or his agent's first knowledge of the defect.
- That CoralVue, Inc. shall be given the first opportunity to make any repairs, replacements, or corrections to the defective construction within a reasonable period of time.
- Under no circumstances shall CoralVue and/or the Manufacturer be liable by virtue of this warranty or otherwise for damage to any person or property whatsoever for any special, indirect, secondary, or consequential damages of any nature, however arising out of the use or inability to use because of the product defect.
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- Unplug your reactor's recirculation pump, isolate your feed line lines, and close the main valve on your pressurized CO2 gas tank to fully depressurize the system.
- Spin the large 7-inch red threaded lid counter-clockwise to remove it from the top of the primary reactor chamber.
- Flip the lid upside down to locate the old, flattened o-ring resting inside the outer circular groove. Use a plastic tool or tooth-pick to gently pry the old ring out. Warning: Never use a sharp metal knife or screwdriver to pry the ring, as you can easily gouge the soft plastic groove and create a permanent leak path.
- Use a soft rag dipped in warm vinegar to thoroughly scrub the empty o-ring channel, removing any trapped calcification, loose aragonite dust, or organic slime.
- Take your fresh ROP-CR-3-5-ORING out of its packaging. Press it firmly into the clean circular channel by hand, ensuring it sits entirely flat without twisting or bunching up.
Pro Tips:
- Always Check for a Hidden Twist in the Silicone Ring During Seating. Because these large 7-inch silicone gaskets are exceptionally flexible, it is very common for the ring to subtly twist on its axis as you push it into the deep under-lid tracking channel. A twisted o-ring creates a tiny uneven high-point along the sealing face. When you screw the heavy red lid down, that small twist will prevent a flush seal, resulting in a slow micro-leak once the recirculation pump fires up. Run your thumb firmly around the entire perimeter of the installed ring to guarantee it sits perfectly smooth and flat.
- Apply a Thin Layer of Reef-Safe Silicone Grease to Extend Operating Lifespan. Whenever you break down your heavy CR3000 or CR5000 reactor to replenish your aragonite coral media, take a moment to lightly coat this silicone o-ring with a high-purity, reef-safe silicone lubricant. Silicone rubber continuously subjected to low-pH aquarium fluid and friction can slowly dry out and become brittle over time. A micro-layer of lubrication helps the heavy threaded lid glide over the rubber without binding or pinching, significantly extending the life of your seal and making future cleanings much easier to open.
- Never Use Harsh Tool Wrenches to Tighten the Threaded Lid Down. Reef Octopus commercial-scale reactors are designed with high-precision threads on their 7-inch red lids to form an effortless compression seal against this thick silicone o-ring. You should always screw the lid down entirely by hand. Never use household strap wrenches, pipe tools, or hammers to force the red lid tighter. Over-tightening the cap doesn't improve the seal; instead, it will over-compress the silicone ring into a permanent flat-spot, warp the top flange, or fracture the clear cast-acrylic walls of your expensive reactor.