PAR Explained
PAR (Photosynthetically Active Radiation) measures the light wavelengths plants use for photosynthesis (400–700 nm).
PAR is measured in μmol/m²/s at the substrate. PAR drops with depth — a 100 PAR fixture at the surface might be 60 PAR at the substrate of a 24-inch tank.
Categories: low light = 15–35 PAR, medium = 35–60 PAR, high = 60–120 PAR.
Spectrum
Plants use red (640 nm) and blue (440 nm) wavelengths most. Green is reflected (which is why plants look green).
Full-spectrum LEDs (5000–8000K) work for any tank.
RGB-tunable LEDs (Chihiros Vivid II, Twinstar) let you boost red for plant color enhancement.
Pure white LEDs work fine but lack the visual pop of RGB.
Top Fixtures (Premium)
ADA Solar RGB: $400–800. Reference standard for aquascaping. RGB tunable, beautiful spectrum.
Twinstar SA: $200–500. Best RGB fixture for the price. Excellent for red plants.
Chihiros Vivid II: $250–500. RGB, app-controllable, sunrise/sunset.
Kessil A360X: $300–500. Spotlight-style, great for nano tanks and shimmer.
Top Fixtures (Mid-Range)
Fluval Plant 3.0: $150–250. Bluetooth-controllable. Great for medium tanks.
NICREW SkyLED Plus: $50–150. Budget RGB. Workhorse fixture.
Hygger Bluetooth LED: $80–150. Sunrise/sunset, RGB. Good budget choice.
Photoperiod
High-tech tanks: 6–8 hours per day.
Low-tech tanks: 6–8 hours per day.
Longer = more algae. Shorter than 6 hours stunts plant growth.
Sunrise/sunset ramps (15–30 minutes each) reduce fish stress.
Tank Depth Considerations
Shallow tanks (12 inches): low-PAR fixtures sufficient.
Standard tanks (18–20 inches): mid-range fixtures.
Deep tanks (24+ inches): high-PAR fixtures or multiple units.
Very deep tanks (30+ inches): consider metal halide pendants or T5HO bulbs alongside LEDs.