?unique=6f69e94)
Octo 300mm Collection Cup O-ring (Regal 300INT/SSS/EXT)
SKU: ROP-CC-ORING-R300
- Factory OEM Replacement: Authentic Reef Octopus replacement collection cup O-ring engineered to exact factory dimensions for a precise compression seal.
- Regal 300-Series Compatibility: Specifically designed for Reef Octopus Regal 300INT and Regal 300SSS in-sump protein skimmers.
- Airtight & Liquid-Tight Seal: Prevents air leakage around the riser neck, preserving the vacuum and internal pressure required for stable foam head formation.
- Stops Skimmate Seepage: Eliminates messy liquid and foam leaks at the cup junction, protecting the exterior skimmer body and sump water from contamination.
- Durable Marine-Grade Elastomer: Resists salt creep, ozone degradation, skimmate acids, and temperature fluctuations without hardening, swelling, or cracking.
- Vibration Dampening Grip: Holds the large 300mm collection cup securely in place while absorbing micro-vibrations from high-flow pinwheel pumps.
Reef Octopus
Globally trusted for premium protein skimmers and pumps, engineered in-house for unmatched reef filtration performance.
Reef Octopus Regal 300 Collection Cup Replacement O-Ring
On massive 300mm-body protein skimmers like the Reef Octopus Regal 300INT and Regal 300SSS, high-volume VarioS controllable DC pumps push massive amounts of air and water through the cone body. The integrity of the foam column as it transitions from the body into the riser neck depends completely on an airtight, pressurized fit. Over years of weekly cup removals, friction, and exposure to aggressive organic fatty acids, the original neck O-ring can stretch, flatten, dry out, or split. A compromised seal leads to micro-bubble leakage, air pressure loss, and greasy liquid skimmate dripping down the outside of the skimmer body back into your sump. The Octo Collection Cup O-ring Regal 300INT/SSS (SKU: ROP-CC-ORING-R300) is the genuine OEM replacement neck seal engineered specifically for Reef Octopus Regal 300-Series Protein Skimmers.
Molded from premium, chemical-resistant marine elastomer, the ROP-CC-ORING-R300 seats into the precision-machined collar groove at the skimmer neck junction. It delivers the exact compression required to seat the heavy 300mm collection cup firmly without jamming, while providing an airtight barrier that forces all rising foam upward through the collection neck. If your current O-ring has become loose, cracked, or causes the cup to wobble during operation, this factory-spec replacement restores seamless sealing, prevents messy leaks, and stabilizes your skimming performance.
Ideal Application & Upgrade Scenarios
If your Regal 300 cup is difficult to twist on/off, if you notice liquid skimmate or salt crust accumulating around the neck collar, or if the original O-ring was damaged or lost during routine maintenance and cleaning, the ROP-CC-ORING-R300 provides an exact drop-in replacement that requires no modifications.
(Note: Package includes (1) Regal 300 Collection Cup Neck O-Ring. Collection cup, lid, skimmer body, and pump sold separately).
What’s Included:
(1) Reef Octopus Regal 300 Collection Cup Replacement O-Ring (ROP-CC-ORING-R300)
Technical Specs:
SKU / Factory Part Identifier: ROP-CC-ORING-R300
Component Type: Collection Cup Neck Sealing O-Ring / Gasket
Target Cup Diameter: 300 mm (~11.8 inches)
Material: Heavy-Duty Marine-Grade Elastomer / Silicone
Color: Black
Chemical Resistance: Ozone Safe, UV Resistant, Skimmate Acid & Saltwater Inert
Compatible Skimmer Models:
Reef Octopus Regal 300-INT (Regal 300INT)
Reef Octopus Regal 300-SSS (Regal 300SSS)
Reef Octopus Regal 300-EXT (Regal 300EXT, where equipped with 300mm slip collar)
Installation & Maintenance Guidelines:
Turn off the power to the skimmer pump and allow the water level inside the skimmer body to equalize.
Carefully twist and lift the 300mm collection cup vertically off the skimmer neck.
Remove the old, stretched, or cracked O-ring from the machined seating groove on the skimmer collar or cup neck using your fingers or a non-marring plastic pick.
Clean the O-ring groove and mating surfaces thoroughly using warm freshwater and a soft microfiber towel to remove dried salt creep, sand grains, and organic residue.
Lightly lubricate the new ROP-CC-ORING-R300 with a thin film of 100% pure food-grade silicone grease (aquarium-safe).
Stretch the O-ring evenly over the neck collar and seat it flat into the designated channel, ensuring there are no twists or folds along its circumference.
Align the collection cup squarely and press it down with a slight twisting motion until fully seated.
Power on the skimmer pump and inspect the collar joint to confirm a complete, airtight, and leak-free seal.
Pro Tips:
- Apply Pure Silicone Lubricant for Effortless Cup Removal. The 300mm collection cup is large and heavy, and a dry O-ring can create excessive friction, making cup removal difficult and risking damage to the acrylic collar. Always apply a thin layer of 100% aquarium-safe silicone lubricant to the ROP-CC-ORING-R300 prior to installation and reapply every few months. This prevents friction binding, ensures a smoother slip fit, and extends the lifespan of the elastomer by shielding it from drying out.
- Check for O-Ring Twisting During Installation. Because of the large diameter of a 300mm O-ring, it can easily roll or twist along its axis when stretched over the collar. A twisted O-ring will not seat evenly into the machined channel, creating high spots that make seating the cup difficult and leaving micro-gaps where skimmate can seep out. Run your index finger smoothly around the entire perimeter of the installed O-ring to confirm it lies completely flat and uniform before sliding the cup back into place.