PHOTOBIO CX 2125 850W 100/277V S4 w/10′ 120V Cord

The PHOTOBIO CX 2125 850W is a compact full-spectrum LED top-light built for commercial and professional horticultural applications. Running at 850W, it delivers 2125 µmol/s photon flux at 277V with 2.5 µmol/J efficacy, making it a direct 1:1 replacement for 1000W double-ended HPS fixtures. The 2.6-inch slim vertical profile keeps vertical space free in dense canopy environments, while passive cooling fins eliminate the need for active airflow across the fixture.

PHOTOBIO CX 2125 Specifications

All specifications below are drawn from the manufacturer product listing (SKU PTB8850LS41). Dimensions are from the product attributes; photon output figures are measured at rated voltage.

Specification	Value
Model / SKU	PHOTOBIO CX 2125 / PTB8850LS41
Photon Flux (PPF) @ 277V	2125 µmol/s
Photon Flux (PPF) — rated	2087 µmol/s
Efficacy (PPE)	2.5 µmol/J
Power Draw	850W
Input Voltage Range	100–277V AC (universal)
Spectrum	S4 Full Spectrum — Osram/Seoul diodes
Dimensions (L × W × H)	24.1″ × 14.2″ × 2.6″
Weight	22.7 lbs (22.72 lbs)
Cooling Method	Passive heat-dissipating fins (fanless)
IP Rating	IP66 (dust-tight, water jet resistant)
Optics	Secondary optics for canopy penetration
Control Interface	iLOC — push-button with digital output display
External Dimming	0-10V via PHOTO•LOC cable; PX Controller compatible
Zone Capacity (PX Controller)	Up to 500 fixtures per zone
Included Accessories	10' PHOTO•LOC 0-10V control cable, 10' 120V power cord, C-clamps
Warranty	5 years

Why Choose the PHOTOBIO CX 2125

The CX 2125 occupies a specific niche: it provides high photon output comparable to a 1000W double-ended HPS system while operating at 850W and fitting into a 2.6-inch vertical footprint. For growers who need to replace HPS infrastructure without rebuilding their hanging systems or reconfiguring room layouts, that combination is practical rather than incidental.

The S4 full-spectrum configuration uses Osram and Seoul Semiconductor diodes selected for their output in the red, far-red, and blue bands. This spectral emphasis supports photosynthetic efficiency across vegetative and flowering stages without requiring separate fixtures for different growth phases. A single fixture type can serve an entire production cycle.

Output control is handled through the onboard iLOC system — a push-button interface with a digital screen showing current output level. This lets operators reduce intensity for younger crops or sensitivity periods without plugging in an external controller. When large-scale zone management is needed, the fixture connects to PHOTOBIO PX Controllers via the included PHOTO•LOC 0-10V cable, with each zone supporting up to 500 fixtures. The IP66 rating keeps the fixture protected in humid greenhouse and indoor environments.

• 2125 µmol/s at 277V: High photon output at 850W power draw, with 2.5 µmol/J efficacy — draws less energy than 1000W HPS while matching or exceeding its photon output.
• Slim 2.6″ profile: The narrow vertical height maximizes growing headroom in low-ceiling rooms and tiered systems where fixture depth matters.
• Passive cooling: No fans means no fan noise, no fan maintenance, and no moving parts to fail over the five-year warranty period.
• iLOC onboard control: Adjust output directly at the fixture without a separate controller; scale to zone control with PX Controllers when needed.
• IP66 weatherproofing: Suitable for humid greenhouse environments; protected against water jets and complete dust ingress.

Best Uses for the PHOTOBIO CX 2125

This fixture is designed for professional production environments where photon output, efficiency, and physical profile all carry weight in the purchasing decision.

• HPS-to-LED conversions: The CX 2125 is built as a 1:1 replacement for 1000W DE HPS fixtures. It uses a similar footprint and hanging configuration, so existing room layouts and racking can typically remain in place. The reduction from 1000W to 850W per fixture lowers electrical load while the 2125 µmol/s output maintains or increases delivered photons at canopy level.
• Commercial cannabis and vegetable production: The S4 spectrum with enhanced red and far-red bands supports dense flowering canopies, and the secondary optics push light deeper into the plant structure rather than concentrating it at the surface. High-density grow rooms benefit from the consistent distribution this provides.
• Humid greenhouse environments: The IP66 rating allows the fixture to operate in greenhouse settings where condensation, irrigation overspray, or humidity levels would compromise unsealed fixtures. The passive cooling design also means no air intake points for moisture to enter.
• Large automated facilities: The PX Controller compatibility — with zone sizes up to 500 fixtures — makes the CX 2125 practical for facilities managing light schedules and intensity levels across hundreds of fixtures simultaneously.
• Multi-stage production rooms: Because iLOC allows output adjustment without external hardware, a single fixture configuration can serve vegetative, transition, and flowering stages by changing intensity levels rather than swapping fixtures.

PHOTOBIO CX 2125 vs 1000W DE HPS Fixtures

The manufacturer positions the CX 2125 directly against 1000W double-ended HPS fixtures, and the comparison is specific enough to be useful for facilities planning a conversion.

Power consumption: A 1000W DE HPS fixture draws 1000W at the lamp plus additional draw from the ballast — typically 1050–1080W at the wall. The CX 2125 draws 850W. Over a 12-hour flowering cycle running 500 fixtures, that difference is roughly 138,000 watt-hours per day — a meaningful reduction in operating cost at commercial scale.

Photon output: DE HPS fixtures in the 1000W class typically deliver 1700–2000 µmol/s depending on reflector quality and lamp age. The CX 2125 delivers 2087–2125 µmol/s from day one, without the lumen depreciation that affects HPS lamps as they age. HPS lamps are typically replaced annually in commercial settings; LED fixtures do not require scheduled lamp replacement.

Heat management: HPS fixtures radiate significant infrared heat downward into the canopy, which affects temperature management and hanging height requirements. LED fixtures, including the CX 2125, emit substantially less radiant heat per photon delivered, allowing closer canopy proximity in some configurations and reducing HVAC load.

Spectrum: 1000W DE HPS produces a broad spectrum weighted toward yellow-orange wavelengths (550–600nm), with relatively less output in the blue and far-red bands. The S4 spectrum in the CX 2125 is engineered with additional red, far-red, and blue content, which some growers find more directly aligned with photosynthetic action spectra for flowering crops.

For growers also evaluating other LED options, the Gavita Pro 1700e LED is another high-output commercial fixture in the same wattage class worth comparing for your room layout.

Compatibility & Operating Range

The CX 2125 accepts universal input voltage from 100V to 277V AC, which covers standard 120V single-phase circuits (as included in this bundle with the 120V cord) through 208V and 240V commercial circuits up to 277V. No voltage selection switch is required — the driver auto-detects input voltage.

Control compatibility:

• PHOTOBIO PX Controllers via PHOTO•LOC 0-10V control cable (included). Up to 500 fixtures per controller zone.
• Standalone operation using the onboard iLOC push-button interface — no external controller required for single-fixture or small-group adjustments.
• The 0-10V control interface is a standard protocol; compatibility with third-party 0-10V controllers should be verified with PHOTOBIO before integration.

Environmental ratings:

• IP66: fully dust-tight; protected against high-pressure water jets from any direction. Suitable for greenhouse and indoor wet environments.
• Passive cooling: no minimum airflow requirement across the fixture face. The heat-dissipating fin design functions in still air, though adequate room ventilation remains necessary for overall environment management.

The included 10-foot 120V NEMA power cord connects to standard 20A or 15A outlets. If operating on 208V or 240V circuits, a different cord configuration is required — see other PHOTOBIO CX 2125 cord variants. For power cord needs in your lighting setup, the Faven Chroma 120V power cords are an example of compatible cord options used in similar LED installations.

Usage Guidelines

Coverage area and hanging height for the CX 2125 depend on crop type, growth stage, and target PPFD at canopy. The following guidelines are derived from the fixture’s output specifications and general LED horticultural practice for this output class.

Recommended hanging heights and coverage:

• Vegetative stage: At 100% output, hang 18–24 inches above canopy. The fixture covers approximately a 4×4 to 5×5 foot footprint at vegetative PPFD targets (200–400 µmol/m²/s). Reduce output via iLOC to 60–70% for seedlings and clones requiring lower intensity.
• Flowering stage: At 100% output, a 4×4 foot canopy footprint is typical for high-density flowering targets (800–1000+ µmol/m²/s). Larger footprints (5×5) are appropriate for moderate PPFD targets or light-sensitive cultivars.
• Output adjustment: The iLOC push-button cycles through preset output levels visible on the integrated digital display. This allows output reduction during early vegetative, transplant recovery, or environmental stress periods without additional hardware.

Photoperiod: The CX 2125 supports standard horticultural photoperiods. For light-deprivation crops, the fixture requires a separate timer or controller to manage on/off scheduling — the PX Controller handles this when multiple fixtures are networked.

Power requirements per circuit: At 850W on a 120V circuit, the fixture draws approximately 7.1A. A standard 20A circuit can support two fixtures with headroom for other loads. At 240V, current draw is approximately 3.5A per fixture, allowing more fixtures per circuit.

How to Install the PHOTOBIO CX 2125

1. Confirm circuit capacity: Verify that the circuit serving the installation point is rated for the fixture’s load. At 120V and 850W, plan for approximately 7.1A per fixture; follow the 80% rule for continuous loads (16A circuit minimum per fixture on a dedicated circuit, or no more than two fixtures on a 20A circuit).
2. Attach hanging hardware: The included C-clamps attach to standard light rails, truss systems, or fixed overhead pipe at up to 1.5-inch diameter. Confirm the hanging point supports the fixture weight plus a safety factor — the CX 2125 weighs 22.7 lbs.
3. Set fixture height: Use ratchet hangers or adjustable cables to position the fixture at the recommended height for your growth stage. Start at 24 inches above canopy for initial setup and adjust based on canopy response and PPFD measurements.
4. Connect the PHOTO•LOC control cable: If using a PX Controller or other 0-10V controller, connect the included 10-foot PHOTO•LOC cable between the controller port and the fixture’s control input. For standalone operation, no cable connection is required — iLOC is accessible directly on the fixture.
5. Plug in the power cord: Connect the included 10-foot 120V power cord to a grounded outlet. Verify the outlet is correctly rated and grounded before energizing.
6. Power on and verify: After powering on, the digital display on the iLOC interface should illuminate and show the current output level. Confirm the fixture is producing light and that the display is functional. If using a PX Controller, verify the fixture responds to controller commands before closing out the installation.
7. Adjust output for growth stage: Use the iLOC push-button to set output to the appropriate level for your current growth stage. Seedlings and clones typically run at 40–60%; established vegetative plants at 70–90%; flowering at 90–100% depending on cultivar and PPFD targets.

For growers newer to LED fixtures or planning a T5-supplemented propagation setup alongside this fixture, the T5 Designer 4ft 4-tube fixture is commonly used in propagation and seedling areas before transitioning crops to high-output LED top-lights like the CX 2125.

Sources & Further Reading