Quick answer: The IceCap In-Sump 40W UV Sterilizer is a plug-and-play UV unit rated for saltwater aquariums up to 400 gallons and freshwater/pond systems up to 3,000 gallons. It ships with a dedicated EVO 2000 feed pump, drops directly into an existing sump chamber with no permanent plumbing, and uses 105 μW/cm² of UVC output to reduce free-floating algae, bacteria, fungi, and parasites without chemicals.
Why UV Sterilization Belongs in a Reef or Fish-Only System
Green water, recurring bacterial blooms, and outbreaks of ich or velvet almost always trace back to microorganisms suspended in the water column rather than anything living on rock or substrate. A UV sterilizer addresses that specific problem: water is pulled through a chamber, exposed to short-wavelength UVC light, and returned to the display or sump. The UVC light disrupts the DNA of algae cells, bacteria, protozoa, and fungal spores as they pass through, without introducing any chemical residue and without harming the beneficial bacteria colonizing your rock, sand, or filter media — because that bacteria never leaves the surfaces it lives on.
For residential reef keepers, this is usually about clarity and disease prevention. For commercial installations — retail systems, medical or research holding tanks, and multi-tank service accounts — UV is often a non-negotiable part of the filtration stack because it reduces pathogen transfer risk across a shared water supply.
IceCap In-Sump 40W UV Sterilizer: Specifications
| Spec | Detail |
|---|---|
| Model | IC-UVR-40INT |
| UV Power | 40W @ 120V |
| Freshwater Capacity | Up to 3,000 gallons |
| Saltwater Capacity | Up to 400 gallons |
| UVC Output | 105 μW/cm² |
| Lamp Length | 15.75″ |
| Lamp Life | 10,000 hours |
| Included Pump | EVO 2000 (30W @ 120V), max 528 GPH |
| Dimensions | 5.4″ x 5.1″ x 24″ |
| Hose Fittings | 1/2″, 3/4″, or 1″ barbed |
Sizing It to Your Tank — and Setting Realistic Flow Expectations
Wattage alone doesn't determine performance; flow rate through the chamber does. UV sterilizers work on contact time, so the goal you're chasing changes the correct flow rate:
- Algae and bacteria control (water clarity): aim for roughly 3–4.5x your total tank volume per hour through the unit.
- Parasite control (ich, velvet, flukes): slow the flow down to roughly 0.5–1.5x total tank volume per hour, since parasites need more contact time with the UVC light to be affected.
This is where sizing conversations get confusing across the industry, and it's worth addressing directly: the 40W unit's included EVO 2000 feed pump tops out around 528 GPH. That flow rate lines up well with parasite-control turnover on tanks in roughly the 200–400 gallon marine range, and comfortably covers algae/bacteria-control turnover on tanks well under that. If you're running a larger system near the top of the unit's rated marine capacity and want maximum bacteria/algae turnover specifically, plan on the included pump as your baseline and know that flow — not wattage — is the lever to adjust. When in doubt, undersizing flow rate is safer than oversizing it: a UV that's run a bit slow still sterilizes effectively, while water pushed through too fast doesn't get enough contact time to matter.
General guidance for freshwater systems is more forgiving, since the 40W model's freshwater rating (3,000 gallons) reflects the lower microorganism density typical of freshwater display and pond setups compared to reef systems.
Installation: What to Expect
The In-Sump 40W is designed to be one of the simpler pieces of equipment you'll plumb into a system:
- Place the unit in an open sump chamber, ideally after your mechanical and biological filtration stages and before water returns to the display.
- Connect the included EVO 2000 feed pump to the base of the housing.
- Route the outflow using the 1/2″, 3/4″, or 1″ barbed fitting that matches your existing hose or tubing.
- Mount the ballast/power supply above and away from any water, secured with the included mounting clips.
- Plug into a GFCI-protected outlet, insert the UV lamp per the included instructions, and let it run continuously.
No permanent bulkheads or drilling are required, which makes it a practical retrofit for an existing sump as well as a planned addition on a new build.
Maintenance
- Replace the UV lamp roughly every 10,000 hours (about once a year) — UVC output drops well before the bulb visibly stops lighting up, so calendar-based replacement matters more than whether the bulb still glows.
- Wipe down the quartz sleeve periodically to clear mineral buildup, which blocks UVC penetration even with a fresh lamp.
- Re-check flow rate after any pump or plumbing changes elsewhere in the system — a change upstream can quietly shift your UV's contact time.
Residential and Commercial Applications
For home reef and freshwater display tanks, this unit is most often chosen when a hobbyist has had a run of cloudy water, recurring algae blooms, or an ich outbreak they want to prevent from recurring. Its 400-gallon marine rating covers the vast majority of large residential display/sump combinations without needing to step up to an external, higher-flow system.
On the commercial side — local fish stores, coral propagation systems, veterinary or research holding systems, and multi-tank maintenance accounts — the drop-in design and 3,000-gallon freshwater rating make it a cost-effective way to add a layer of pathogen control to a shared water system without a full custom UV installation.
Frequently Asked Questions
Does the IceCap In-Sump 40W UV Sterilizer work for both saltwater and freshwater?
Yes. It's rated for saltwater aquariums up to 400 gallons and freshwater or pond systems up to 3,000 gallons, and ships ready to run in either application.
Will it harm my beneficial bacteria or corals?
No. UVC light only affects organisms suspended in the water column as they pass through the sealed chamber. Beneficial bacteria colonizing your rock, sand, and filter media, along with your corals and fish, are never exposed to the UV light directly.
Can a UV sterilizer cure ich or velvet on its own?
A properly sized and flow-tuned UV sterilizer reduces the free-swimming stage of these parasites in the water column, which can meaningfully lower reinfection pressure. It should be treated as one part of a broader husbandry and quarantine strategy rather than a standalone cure.
How often does the lamp need to be replaced?
Roughly every 10,000 hours, or about once a year of continuous use, since UVC output declines well before the bulb stops lighting.
Do I need to buy a separate pump?
No. The 40W model includes an EVO 2000 feed pump (528 GPH max) sized for the unit, so it's ready to install as a complete kit.
Ready to Add UV Sterilization to Your System?
The IceCap In-Sump 40W UV Sterilizer is available now at Marine Concept Supply, and our team can help you confirm sizing before you order — whether it's for a home reef, a freshwater display, or a commercial system. Stop by our Wheeling, IL showroom, browse our full lineup of UV sterilizers, or reach out and we'll walk through flow rate and installation for your specific setup.
