Description
Stop Guessing Light Levels and Measure What Your Plants Receive
The PHOTOBIO Advanced Quantum PAR Meter is a handheld light meter built for horticulture. Its remote quantum sensor reads PAR between 400 and 700 nm and shows the result as PPFD in µmol/m²/s across a range of 0 to 3,999, so you see the light that actually drives photosynthesis rather than the lux or lumen figures a general light meter gives. It reads LED, HPS, MH and CMH grow lights accurately, stores up to 99 readings, and comes with two sensor cables and a protective carry case, making it a practical tool for a single grow tent, a multi-light grow room or a commercial greenhouse.
Key Benefits
- True quantum PAR sensor – measures 400–700 nm (±10 nm), the band plants use for photosynthesis
- Wide 0–3,999 µmol/m²/s range – covers anything from propagation lights to full-power flowering fixtures
- Repeatable readings to 1 µmol/m²/s, so changes in height or dimming show up clearly
- Remote sensor on a coiled or a 12 ft straight cable – read the canopy while the display stays outside the light
- 99-reading memory for mapping a whole canopy before you adjust anything
- Works with every grow light type – full-spectrum LED, HPS, MH and CMH
Uneven Canopies and Wasted Light
Most lighting problems are invisible to the eye. A fixture hung too high leaves plants stretching for light, with long gaps between nodes and slow growth, while one hung too low, or run at full power over young plants, causes light stress, bleached leaves and wasted electricity. Even a well-placed light is rarely uniform: the centre of a grow tent can read twice the edges. Mapping PPFD across the canopy shows exactly where the hotspots and shaded corners are, so you can set height, dimming and plant spacing for even light intensity and steady plant health from vegetative growth through flowering.
How to Use
- Set up: fit the two AAA batteries and connect the remote sensor with the short coiled cable for handheld checks, or the long straight cable to read inside a closed tent
- Position the sensor: keep the white diffuser clean, level and facing straight up at the top of the canopy
- Map the space: take readings at the centre, edges and corners and save them to the memory to compare
- Adjust: too low, lower the light or turn the dimmer up; too high, raise or dim it, then measure again
- Typical targets: 100–300 µmol/m²/s for cuttings and seedlings, 300–600 in vegetative growth, 600–900 in early flowering and up to 900–1,200 for light-hungry fruiting and flowering crops at peak; leafy greens and herbs sit towards the lower end
- Re-check whenever plants change stage, a fixture is moved or a lamp is replaced
Technical Specifications
- Brand: PHOTOBIO (Phantom)
- Measures: PAR as PPFD (µmol/m²/s)
- Spectral range: 400–700 nm ±10 nm
- Measurement range: 0–3,999 µmol/m²/s
- Repeatability: 1 µmol/m²/s
- Memory: up to 99 readings
- Sensor: remote quantum sensor with white diffuser
- Cables: short coiled cable and 12 ft (approx. 3.7 m) straight cable
- Compatible light sources: LED, HPS, MH and CMH
- Power: 2 × AAA batteries (included)
- In the case: main unit, remote sensor, two connection cables, 2 × AAA batteries, protective carrying case
Frequently Asked Questions
Why use a PAR meter instead of a lux meter or a phone app?
Lux meters weight their reading to human eyesight, which is most sensitive to green light, so they misread red-heavy HPS and the red and blue peaks of many LEDs. A quantum PAR sensor counts photons evenly across 400–700 nm, which is the measurement grow-light PPFD figures are quoted in.
Is it accurate under LED grow lights?
Yes. It is made for horticultural lighting and suits full-spectrum LED as well as HPS, MH and CMH fixtures.
Can I take readings without opening the tent?
Use the 12 ft straight cable: leave the sensor on the canopy and read the display from outside, so the environment inside stays undisturbed and your eyes stay out of the direct light.
What PPFD should I aim for?
As a guide, 100–300 µmol/m²/s for cuttings and seedlings, 300–600 in vegetative growth and 600–1,200 through flowering and fruiting, depending on the crop and whether you add CO2. Raise intensity gradually and watch the leaves for stress.
Works Well With
