In-store pickup only.
The Red Sea Reefer RSK-900 is a premium, performance-tuned in-sump protein skimmer designed for large reef aquariums. Matched precisely to the Reefer 525XL/625/750 and similarly sized systems, it uses Red Sea’s signature flow dynamics to hold an optimal ORP (REDOX) level of 350 mV+ — the level normally associated with ozone treatment — for exceptional water clarity and reef health.
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Features
- Premium in-sump skimmer for large saltwater reef systems
- Maintains ORP of 350 mV+ for ozone-level water clarity
- High-performance needle-wheel pump
- Quiet operation suitable for in-home display systems
- Designed for the Reefer 525XL, 625, and 750 sump
- Red Sea’s hobbyist-focused engineering and build quality
Specifications
| Brand | Red Sea |
| Product | Reefer RSK-900 Protein Skimmer |
| Footprint | 11.4″ x 10.6″ or 12.6″ x 9.4″ |
| Height | 23″ |
| Suitable For | Saltwater reef aquariums |
| UPC | 730773505098 |
| SKU | R50509 |
| Condition | New |
FAQ
What size tank is this for?
The RSK-900 is sized for Red Sea’s larger Reefer systems (525XL, 625, 750) and comparably sized reef aquariums up to ~200 gallons, depending on bioload.
Is this a drop-in for the Reefer sump?
Yes — the RSK-900 is engineered to fit directly into the Reefer XL/G2 series sump’s skimmer chamber.
Does this come with a pump?
Yes — the skimmer ships with its matched needle-wheel pump.
Can I pick this up in-store?
Yes — this item is in-store pickup only. We do not ship this product.
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