PHOTOBIO CX 2125 LED 850W 100/277V S4 (10′ 208-240V Cord)

The PHOTOBIO CX 2125 LED 850W is a compact, high-output full-spectrum top light designed for horticultural professionals. Delivering 2125 umol/s photon flux at 277V and 2.5 umol/J efficacy, it is built as a direct 1:1 replacement for 1000W DE HPS fixtures. Its 2.6-inch slim profile, passive cooling fins, and iLOC integrated dimming control make it well-suited for commercial grow rooms where ceiling height, heat management, and output flexibility all matter.

PHOTOBIO CX 2125 Specifications

Specifications sourced from the canonical product data and manufacturer feature list (SKU: PTB8850LS42).

Specification	Value
Power Draw	850W
PPF (Photosynthetic Photon Flux)	2087 umol/s
Photon Flux at 277V	2125 umol/s
Efficacy (PPE)	2.5 umol/J
Spectrum	S4 Full Spectrum (Osram/Seoul diodes)
Spectral Output	Enhanced red, far-red, and blue wavelengths
Dimensions (L x W x H)	24.1″ x 14.2″ x 2.6″
Weight	22.7 lbs (22.7204 lbs)
Input Voltage	120–277V
Included Cord	10-foot 208-240V power cord
Control Interface	iLOC push-button with digital screen
Control Cable	10-foot PHOTO·LOC 0-10V control cable (included)
IP Rating	IP66
Cooling Method	Passive heat-dissipating cooling fins
In-Box Accessories	C clamps, 10-ft 208-240V cord, 10-ft PHOTO·LOC cable
Warranty	5 years

Why Choose the PHOTOBIO CX 2125

The CX 2125 sits at the top of the PHOTOBIO lineup in photon output. Here is what separates it from a standard LED fixture upgrade.

• Direct 1000W DE replacement with comparable footprint: The CX 2125 is engineered to drop into the same hanging position as a 1000W double-ended HPS fixture. The 24.1 x 14.2-inch footprint mirrors the distribution pattern growers are already used to, which reduces reconfiguration time when switching technology.
• Slim 2.6-inch profile preserves vertical space: At just 2.6 inches tall, the fixture sits close to the hanging point. In rooms with limited ceiling height, the extra headroom translates directly to usable grow space between the canopy and the light.
• Passive cooling — no moving parts to fail: Heat dissipation relies entirely on aluminum cooling fins rather than fans. There are no fan motors to burn out, no noise, and no maintenance on the thermal management system.
• iLOC push-button dimming with digital readout: The integrated iLOC interface lets growers step light output up or down based on crop stage without external controllers. A digital screen confirms the current output level directly on the fixture.
• Compatible with Autopilot PX Controllers: When scaling to larger rooms, the CX 2125 accepts 0-10V dimming signals from Autopilot PX Controllers, supporting up to 500 fixtures per zone for facility-wide scheduling and ramping.
• S4 Full Spectrum with Osram/Seoul diodes: The S4 spectrum emphasizes red, far-red, and blue wavelengths that directly drive photosynthesis and flowering. Both Osram and Seoul diodes are established horticultural component suppliers with documented efficacy data.
• IP66 rating and 5-year warranty: IP66 means the fixture handles dust ingress and water jets, making it suited for humid grow environments. The 5-year warranty covers the fixture against manufacturing defects over a commercially relevant service life.

Best Uses for the PHOTOBIO CX 2125

The CX 2125 is designed for professional cultivators running high-density commercial grows. The following use cases reflect what the fixture is built for.

• Commercial flower rooms replacing 1000W DE HPS: The CX 2125 was explicitly designed as a 1:1 replacement for 1000W double-ended HPS fixtures. Operations converting existing rooms benefit from the matching footprint and comparable canopy distribution, reducing the need to respace hangers or restructure benching.
• High-density indoor production with restricted ceiling height: The 2.6-inch vertical profile means growers can hang the fixture closer to the ceiling support without sacrificing the mounting angle. This is directly useful in rooms where overall ceiling height limits how high a fixture can be positioned.
• Multi-zone facilities using Autopilot PX Controllers: Large grows running Autopilot PX Controller infrastructure can integrate the CX 2125 directly via the PHOTO·LOC 0-10V cable. Up to 500 fixtures can be controlled per zone, making coordinated sunrise/sunset schedules and stage-based intensity adjustments practical at scale. For growers evaluating a high-output LED alternative, the CX 2125 competes at a different power and footprint point.
• Wet or humid environments requiring IP-rated fixtures: The IP66 enclosure rating means the CX 2125 handles condensation, nutrient mist, and direct water splashing. Growers running aggressive humidity protocols or regular pressure washing of room surfaces have a fixture that can withstand the environment.
• Operations where passive cooling matters: Grows with strict ambient temperature targets benefit from removing fan-cooled fixtures that add small incremental heat loads and introduce noise. Passive fins on the CX 2125 transfer heat silently without adding airflow complexity to the room.

PHOTOBIO CX 2125 vs Similar LED Top Lights

The CX 2125 occupies the 850W class of commercial LED top lights. Compared to other fixtures in this power range, several practical differences are worth noting.

The CX 2125’s 2.5 umol/J efficacy sits at a commercially competitive level for high-wattage LED fixtures. The slim 2.6-inch height is a meaningful distinction — many 800-1000W LED fixtures run taller drivers and heatsinks that add 4 to 6 inches of vertical depth. The CX 2125’s passive cooling design removes the fan-failure point that affects active-cooled competitors, though passive designs do require adequate room airflow to prevent thermal buildup at the fixture surface.

The iLOC on-board dimmer is a useful feature for operations that want per-fixture manual control without a networked controller. Growers who need coordinated multi-zone dimming across a full facility will still want to pair the CX 2125 with Autopilot PX Controllers or equivalent 0-10V infrastructure, since the iLOC handles individual output levels rather than zone scheduling. Fixtures from other manufacturers in this wattage class may offer different controller ecosystems, so controller compatibility is worth checking before committing to a mixed-brand room.

The S4 full spectrum covers the wavelength bands most relevant to vegetative growth and flowering. Growers evaluating this fixture alongside other options should compare PPF, efficacy (umol/J), and spectrum charts from each manufacturer under the same test conditions before making a room-level decision.

Compatibility & Operating Range

The PHOTOBIO CX 2125 accepts input voltage from 120V to 277V, making it compatible with standard 120V residential circuits as well as 208V and 240V commercial circuits. The included 10-foot cord is terminated for 208-240V use. For 120V installations, use an appropriately rated 120V cord and verify the circuit’s amperage capacity for 850W draw.

The fixture communicates via 0-10V analog signal through the included PHOTO·LOC control cable. This standard signal type is compatible with Autopilot PX Controllers (up to 500 fixtures per zone per the product documentation) and any other 0-10V compatible lighting controller. Growers already running Autopilot infrastructure will find the CX 2125 integrates without additional adapters.

The IP66 enclosure rating means the fixture is suitable for environments exposed to dust and direct water jets. This covers most commercial indoor horticulture conditions, including rooms with active humidification, regular rinse-downs, and nutrient spray systems. Check that mounting hardware (ratchet hangers, light rails) is rated for the 22.7 lb fixture weight before installation.

For growers running varied lighting across different areas of a facility, the CX 2125 can be used alongside propagation lighting such as a T5-equipped propagation setup for seedling and clone stages before plants move under the CX 2125 for the main growth cycle.

Usage Guidelines

Coverage area and hanging height depend on crop type and growth stage. The CX 2125 replaces a 1000W DE HPS fixture, so initial positioning can follow the same spacing and height guidelines used for the legacy fixture. As a general reference for high-output LED top lights in the 850W class:

• Vegetative stage: Hang higher (typically 24–36 inches above canopy) and use iLOC to reduce output to 50–75% to avoid light stress on young growth. Increase output and lower height as the plant canopy fills in.
• Flowering/fruiting stage: Move to full or near-full output. Standard spacing for a 1000W DE replacement in flower is approximately one fixture per 4×4 to 5×5 foot area, though actual coverage depends on PPFD targets, reflective wall treatment, and crop type.
• iLOC dimming: Use the push-button interface on the fixture end to step output levels up or down. The digital screen confirms the selected output. For automated stage-based dimming across multiple fixtures, connect the PHOTO·LOC 0-10V cable to an Autopilot PX Controller or compatible 0-10V controller.
• Secondary optics: The CX 2125 uses secondary optics for canopy penetration. Orient the fixture parallel to the longest plant row dimension for consistent distribution across the footprint.
• Thermal management: Passive cooling fins require ambient airflow. Ensure room circulation fans move air across the fixture surface. The fixture should not be installed in a sealed, unventilated space.

Verify PPFD at canopy level with a quantum meter when first setting up the room. Adjust hanging height based on measured readings rather than estimated coverage charts alone.

How to Install the PHOTOBIO CX 2125

1. Plan mounting positions: Mark hanging points on the ceiling support structure based on your fixture spacing plan. For a 1:1 1000W DE replacement, use the same spacing as the legacy fixtures. Confirm each point can bear more than 22.7 lbs with appropriate safety factor.
2. Attach C clamps: Use the included C clamps to secure ratchet hangers or a light rail track to the ceiling support. Do not use the clamps on structures that are not rated for the combined fixture and hardware load.
3. Hang the fixture: Hook ratchet hangers through the fixture mounting points and raise to the initial hang height for the growth stage. Leave slack in the hangers to allow height adjustment once power is confirmed.
4. Connect the power cord: Plug the included 10-foot 208-240V cord into a compatible 208V or 240V outlet or hardwired circuit. For 120V circuits, a separate 120V-rated cord is required. Verify the circuit breaker rating covers the 850W draw with appropriate headroom.
5. Connect the PHOTO·LOC control cable: If using an Autopilot PX Controller or other 0-10V dimming system, connect the included 10-foot PHOTO·LOC cable between the fixture and the controller. If using iLOC manual dimming only, the control cable is not required for basic operation.
6. Power on and verify: Switch on the circuit. The digital screen on the iLOC interface should illuminate and display the current output level. If the fixture does not power on, check cord seating and circuit breaker status.
7. Set initial output level: Use the iLOC push-button to set the appropriate output level for the current crop stage. Verify with a quantum meter at canopy level.
8. Adjust hang height: Fine-tune hang height based on measured PPFD readings and target light levels for the growth stage. Ratchet hangers allow adjustment without tools.

For multi-zone controller setup, refer to the Autopilot PX Controller documentation for zone wiring and fixture addressing. The PHOTO·LOC 0-10V cable from each fixture connects to the corresponding controller output channel.

Sources & Further Reading