coospider-repta Aquarium UV Light 18W — Submersible UV-C Clarifier for 100–1000 gal, Dual-Tube Quartz Sleeve

coospider-repta 18W Aquarium UV Light is a submersible UV-C clarifier designed to reduce free-floating algae and suspended particles in ponds, pools, spas, cold plunge tubs, and large tanks from 100 to 1000 gallons.

Keep water clearer and more visually appealing without chemical overdosing: this 18W UV clarifier uses dual-tube UV-C technology inside a high-transparency quartz sleeve, a weighted gravity block for stable sinking, and a long 17-foot cable to reach filters or deep pond locations. The unit is engineered for continuous or timed short runs, with multi-level sealing for underwater reliability and an expected service life of about 8,000 hours. Updated packaging and installation parts reduce breakage risk and make setup easier.

How does this UV light help clear pond or tank water?

The unit emits focused UV-C wavelengths that affect microorganisms and microalgae in the water column as they pass near the lamp, helping reduce green water and organic haze over repeated use. It’s not a filter replacement but complements mechanical and biological filtration to improve overall clarity.

• Dual-tube UV-C design for more consistent output and longer, stable operation
• High-transparency quartz glass improves UV penetration into surrounding water
• Best used in line with pump flow or inside filter chambers for maximum contact

Where and how should I install the 18W UV clarifier?

The clarifier can be placed inside a pond filter, filter screen, large aquarium filter housing, or positioned directly in the pond where it will stay submerged. The included gravity block lets the unit rest on the pond bottom while the 17-foot cable reaches your power source safely.

• Submerge in filter chamber or pond area with steady flow for continuous treatment
• Use opaque boards in tanks to isolate UV exposure from fish light-sensitive areas
• Follow the provided installation video and keep power source dry and protected

How long and how often should I run the UV lamp?

Recommended daily use is typically 1–2 hours for maintenance in ponds and large tanks; heavier algae blooms may require longer or continuous running until clarity improves. Results depend on water volume, flow rate through the lamp area, and the overall filtration system.

• Start with 1–2 hours daily for maintenance in 100–1000 gallon systems
• Increase runtime during heavier algae outbreaks, then reduce after clarity returns
• Monitor flow and lamp placement to ensure water passes near the quartz sleeve

What safety and maintenance steps do I need to follow?

UV-C is harmful to skin and eyes; never operate the lamp outside its sealed sleeve or view it directly. The quartz sleeve should be kept clean to maintain UV efficiency, and seals inspected periodically to ensure waterproof integrity.

• Always handle with power disconnected and keep out of reach of children
• Clean quartz sleeve periodically to prevent deposits that block UV transmission
• Replace the UV tube near 8,000 hours of use and check seals for wear

Who is this for: The coospider-repta 18W UV Pond Light is aimed at pond keepers, koi owners, managers of larger aquariums, and anyone using cold plunge tubs, spas, or outdoor pools who wants to cut down on suspended algae and improve water clarity without relying solely on chemicals. It’s suited to systems with reliable circulation where a submersible lamp can be positioned near the water flow or inside filtration plumbing. If you need straightforward, supplemental water clarification for systems between roughly 100 and 1000 gallons and are comfortable with occasional lamp maintenance and safe handling, this unit provides a compact, installable solution backed by a one-year warranty and installation resources.