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Ships within 48 hours · Estimated delivery Nov 12 - Nov 17
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Description
cmh grow light bulb Growers Choice Horticultural Lighting 315W SE CMH Complete Fixture 3KGrower's Choice 315W CMH Grow Light Happy Hydro Full spectrum light that actually matches sunlight, at 315 watts The Grower's Choice GC 315 is a complete ceramic metal halide fixture with a built in digital ballast, open reflector, and your choice of lamp spectrum. CMH produces a broader, more balanced spectrum than HPS with a CRI up to 97, which means your plants see light closer to what they'd get outdoors. The fixture runs 120V 240V, dims without
Full-spectrum light that actually matches sunlight, at 315 watts
The Grower's Choice GC-315 is a complete ceramic metal halide fixture with a built-in digital ballast, open reflector, and your choice of lamp spectrum. CMH produces a broader, more balanced spectrum than HPS with a CRI up to 97, which means your plants see light closer to what they'd get outdoors. The fixture runs 120V/240V, dims without external controllers, and includes full circuit protection so you're not replacing ballasts after a power surge.
- Narrow spectrum, heavy in yellow/orange, almost no UV or blue
- 600W draw plus additional cooling costs
- Separate ballast, reflector, socket, and lamp to assemble
- Magnetic ballasts hum, flicker, and lose efficiency over time
- Bulbs degrade quickly, typically need replacement every 6 to 9 months
- No built-in dimming or fault protection
- Full spectrum with UV, blue, red, and far-red, CRI up to 97
- 315W draw, nearly half the power for competitive PAR output
- All-in-one fixture: ballast, reflector, and lamp in one unit
- Digital square-wave ballast, no hum, no flicker, consistent output
- 15,000-hour rated lamp life, roughly double a standard HPS bulb
- Built-in dimming dial and full circuit protection against surges
Closest spectrum to sunlight available in HID CRI up to 97
The 4K lamp scores a 97 CRI, meaning its spectral output is nearly identical to natural daylight. The 3K lamp sits at CRI 90 with enhanced red for flowering. Plants respond to this broader spectrum with tighter internodal spacing and more uniform growth.
Low-frequency square wave ballast
The digital ballast drives the lamp with a low-frequency square wave, which is up to 30% more efficient than magnetic ballasts and maintains that efficiency for the life of the unit. No internal fans needed because the case design acts as a passive heat sink.
Full circuit protection with 3-second self-test
On every ignition, the ballast runs a 3-second diagnostic. It protects against open circuit, short circuit, over-voltage, under-voltage, and over-temperature faults. If something is wrong, the ballast enters protection mode instead of damaging itself or the lamp.
Dimmable with Smart Step and Super Lumen modes
Turn the dial to reduce output when plants are young or temperatures are high. Super Lumen pushes the lamp past rated wattage for maximum PAR when you need peak intensity during late flower.
Runs cooler than HPS at comparable PAR
At 315W, this fixture produces significantly less radiant heat than a 600W HPS. In small tents or rooms without dedicated HVAC, that can be the difference between manageable temperatures and constant heat stress.
Compatible with Grower's Choice Master Controller
Daisy-chain up to 100 fixtures per zone using the optional Master Lighting Controller. Supports timed on/off, sunrise/sunset ramping, and dual thermal probe auto-dim shutdown for commercial setups.
Setting up your GC-315
Hang the fixture
Use the included hanging hardware to mount the fixture from your tent crossbars or ceiling hooks. Adjust height to 18 to 24 inches above the canopy for flowering, 24 to 30 inches for veg.
Install the lamp
Insert the 315W CMH lamp into the built-in socket. The lamp seats horizontally in the open reflector. Handle by the base only, not the glass envelope.
Set the power level
Turn the ballast dial to your preferred output. Start lower for seedlings or clones, then step up to full power as plants mature. Use Super Lumen mode during peak flower if temperatures allow.
Plug in and grow
Connect to any standard 120V outlet (ships with a 120V plug). For 240V operation, swap the cord end or hardwire. The ballast auto-detects frequency and adjusts output to prevent flicker.
- GC-315W all-in-one fixture with integrated digital ballast
- One 315W CMH lamp (your choice of spectrum)
- Open reflector with horizontal lamp mount
- 120V power cord (pre-attached)
- Hanging hardware
- 3-year manufacturer warranty
- 3K-R (3,100K): Full spectrum optimized for bloom, enhanced red, CRI 90, 570 µmol/s
- 4K (4,200K): Veg-optimized with heavy blue output, CRI 97, promotes tight internodal spacing
- 10K MH Finishing: Metal halide finishing lamp for the final 2 weeks, boosts resin and aroma
- No Bulb: Fixture only, bring your own 315W SE CMH lamp
Questions? We're easy to reach.
Happy Hydro has been serving growers since 2006. Call or email us before you order, after you order, or any time something comes up. When you're happy, we're happy.
Shipping Notes
- Free Standard Shipping on $100+ Orders to the USA.
- Except Preorder products are shipped in 48 hours.
- Delivery to the USA:
- Standard Shipping : 3-10 business days
- If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
- We offer a 30-day return/exchange service after receiving.
- Final sale items are not eligible for returns or exchanges.
- To process your return/exchange, please contact us at [email protected]
- Please click here for more details>>> Return & Exchange Policy