Large-Format Reef Sump for 250 to 350-Gallon Aquariums with Dual 7-Inch Filter Sock Holders
The IceCap 48 Reef Sump V2 is a purpose-built acrylic reef sump for large reef aquariums in the 250- to 350-gallon range. Its 48 x 22 x 16-inch footprint and infrastructure are scaled to the flow rates, equipment sizes, and maintenance demands that large-format reef systems require. Also features three 1.5-inch intake drains instead of the dual 1-inch drains of the SS15 and SS24, dual 7-inch filter sock holders in place of the single 4-inch holder of the smaller models, a 24.8 x 21.6-inch skimmer section that comfortably fits serious in-sump protein skimmers, and a 9.8 x 21.6-inch return pump section with enough room for a high-flow return pump alongside reactors, an ATO reservoir, and dosing lines.
The V2 update to the SS48 made several meaningful changes. The freshwater reservoir was removed, consolidating the internal footprint for equipment use. Multiple 4-inch filter sock positions were replaced with the current dual 7-inch sock holder configuration; a significant upgrade for high-flow systems where a 4-inch sock loads and restricts quickly. New 1.5-inch intake drains were added, and built-in twin heater holders replaced V1's suction-cup approach. IceCap confirms that the exterior dimensions, skimmer compartment, and return sections are unchanged from V1.
The 7-inch filter sock holders are a perfect fit for the Klir Di-7 Auto Fleece Filter (sold separately), which automates filter sock advancement and eliminates manual sock changes in a system where high-volume mechanical filtration is one of the most frequent maintenance tasks. IceCap specifically recommends the K3-200INT In-Sump Protein Skimmer as the matched skimmer for the SS48's 24.8 x 21.6-inch skimmer section.
Key Features:
- For reef aquariums ranging from 250 to 350 gallons
- Footprint: 48 x 22 x 16 in (LxWxH)
- Durable acrylic construction
- Bubble-diffusing intake chamber prevents microbubbles from reaching the return section
- Triple 1.5-inch intake drains for high flow volume (V2 update)
- Dual built-in 7-inch filter sock holders with 200-micron sock prefilters included (V2: replaced multiple 4-in socks)
- Perfect fit for Klir Di-7 Auto Fleece Filter (sold separately)
- Skimmer section: 24.8 x 21.6 in — accommodates full-size in-sump protein skimmers including IceCap K3-200INT
- Return pump section: 9.8 x 21.6 in — ample room for return pump, reactors, and dosing equipment
- Twin heater holder — built-in (V2 update)
- Emergency drain holder
- Triple probe holder and four-slot tubing holder
- Adjustable water depth: 5 to 9 inches
- Compartment lids for quiet operation
- V2 change: freshwater reservoir removed; filter socks consolidated from multiple 4-in to dual 7-in; exterior dimensions unchanged from V1
- Freight shipping
What Changed in V2 vs V1:
- Freshwater reservoir: Removed
- Filter sock configuration: Multiple 4-in positions replaced with dual 7-in holders
- Intake drains: New 1.5-in drains added
- Heater mounting: New built-in twin heater holder added
- Exterior dimensions, skimmer section, and return section: Unchanged from V1
Ideal For:
- Reef hobbyists running large display systems of 250 to 350 gallons who need a sump scaled to the flow rates and equipment requirements that large-format reef filtration demands — not adapted from a smaller unit
- Existing IceCap SS48 V1 owners who want the V2 improvements, dual 7-inch sock holders, built-in heater mounts, new drains, without needing to resize or replumb since exterior dimensions are unchanged
- Reef installers, professional maintenance technicians, and experienced reefers who need a proven, purpose-built sump that accommodates a full equipment roster including a large in-sump skimmer, calcium reactor, refugium, kalkwasser doser, and multiple sensors in clearly organized sections
Pro Tips:
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Pair with the Klir Di-7 V2 for the 7-inch sock holders before your first fill. At 250 to 350 gallons of display tank volume with typical reef stocking, a 7-inch filter sock on a manually maintained schedule will load fast — particularly during the first few months after rock curing, new coral additions, and feeding spikes. The Klir Di-7's automated fleece advancement removes manual sock changes entirely and is worth installing from day one rather than retrofitting after the system is running.
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Use the IceCap Freshwater ATO Reservoir to replace the removed built-in reservoir. All V2 IceCap sumps had the built-in freshwater reservoir removed. On a 250 to 350-gallon reef, evaporation is substantial — a system this size typically evaporates 1 to 2+ gallons per day depending on temperature and airflow. The IceCap Freshwater ATO Reservoir sold separately provides the dedicated ATO water storage that the V2 sump no longer includes, sized appropriately for the evaporation demands of a large system.
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Map out the return section before filling. The 9.8 x 21.6-inch return section provides meaningful space, but a 350-gallon system may run a high-flow DC return pump, a calcium reactor effluent line, a kalkwasser doser connection, an ATO float probe, multiple controller probes, and a dosing pump input — all in this section simultaneously. A pre-fill sketch of what goes where prevents the return section from becoming a cable management problem after the sump is running.
