Continuing in the same vein as my previous LED lighting tests over the years, this article presents data on light intensity and spread, along with the spectral distribution of light for some new and latest-generation LED fixtures. Table 1 presents a list of the LED lighting fixtures reviewed in this article.
Each of these was tested using the same setup as my previous tests, using a 3’X3’ grid with a spacing of 3” in the X, and Y direction. The fixtures were centered on this grid and oriented such that the length was along the Y-axis. PAR was measured as PPFD (Photosynthetic Photon Flux Density) in micromoles/m2/sec using a LICOR 1000 data logger and a LI-192SA underwater cosine corrected sensor calibrated for both air and water.
The data logger was set to average 5 readings for each data collection point. All measurements were made in air. The data was imported into Microsoft Excel for analysis plotted to display the light spread and intensity at 24” and 30” from the light source. 4 plots of the data with 2 plots at each distance were generated showing:
- A 3-D surface plot showing the actual PAR values recorded
- A contour plot viewing the surface from the top showing the distribution and spread on the 3ftX3ft grid
A UPRtek spectral PAR meter PGN100 was used to collect data on the spectral characteristics of the light generated by these fixtures. The PGN100 provides the spectral plot in the form of a normalized spectrum, normalized by setting the peak output equal to 1.
In addition to the spectral plot the measurement also provides other pieces of information such as PPFD (Photosynthetic Photon Flux Density measured in micromoles/m2/sec), and lumped PFD (Photon Flux Density) in different ranges for UV, Blue, and Green, Red and Far Red (FR).
The PPFD excludes the UV and IR portions, but the PGN100 has a measuring range of 380-780 nm and can report measurements in this range, UV (380-400nm) and Far Red range (700-780nm). The Uspectrum software was used to generate the reports on the data collected. All spectral measurements were made at 23.25” from the center of the LEDs.
The color produced by the light is quantified using the CIE diagrams which specify the color in terms of a coordinate system. The black body curve is also included in this diagram and shown as a line corresponding to different color temperatures. A light with low coordinates on both the axis would indicate a strongly blue light, and deviating extremely from the black body curve. Such a light will not have a quantifiable CCT (correlated color temperature).
Power draw was measured by a MECHEER power meter plug. The power measurements show the actual wall plug power pulled by the LED fixtures.
Table 1: LED Lighting Fixtures Tested
| LED Fixture | Picture |
|---|---|
| Radion G6 XR30 PRO |  |
| GNC Bluray X |  |
| AI Blade Coral Grow 21” |  |
Test Data and Analysis
Radion G6 XR30 Pro – Spectral Analysis
The Radion G6 XR30 PRO uses 100 LEDs in the fixture with the following distribution as per the provided specifications by the manufacturer and shown in Figure 1. Cooling is actively provided by a fan. The physical size is 11.8” X 7” X 1.5” with a weight of about 4.5 lbs.
Figure 1 . LEDs used in the Radion G6 XR30 PRO. (source – https://ecotechmarine.com/wp-content/uploads/2022/04/G6-30-Pro.webp )
Figure 2, shows the spectral analysis of the Radion G6 XR30 PRO as reported by the PGN100N spectral PAR meter. The measurements were recorded at a distance of 23.25” from the fixture. The peak output is at 449 nm.
Figure 2 – Spectral Analysis of the Radion G6 XR30 Pro
Figure 3 shows the spread and intensity as measured at the 169 points on the 3X3ft grid. This distribution and intensity is due to the optics and the light output of the LED fixture. Peak values obtained at 24” were 173.2 micromoles/m2/sec, and 111.7 micromoles/m2/sec at 30”. The light is quite well spread as indicated by the areas covered by the intensity ranges.
Figure 3. Radion G6 Light Intensity and Distribution at 24” and 30”
GNC Bluray X
The GNC Bluray X has a larger footprint of 15.7X11.8 with a height of 1.6”. It uses a large heavy heatsink and eliminates the fan for cooling, with a fixture weight of 12.3 lbs. The approach taken is to use a large number of LEDs – 536 in this case, in the following combination, shown in Table 2.
Table 2: Distribution and number of LEDs used in the GNC Bluray X.
| LED Type | # of LEDs |
| Blue 460nm | 308 |
| White 12,000K | 169 |
| Red 660 nm | 12 |
| UV 405 nm | 22 |
| UV 420 nm | 22 |
| Blue Moon – 460 nm | 2 |
| White Moon 6500K | 2 |
The arrangement of the LEDs is shown in Figure 4 below (source – https://www.gncbluray.com/2024/02/17/uno-zoom-su-bluray-x-la-nuova-piastra/)
Figure 3. Arrange of the LED Array for the GNC Bluray X
Figure 4, shows the spectral analysis of the GNC Bluray as reported by the PGN100N spectrophotometer. The measurements were recorded at a distance of 23.25” from the fixture, as a single-point reading at the center of the LED fixture. The spectral analysis shows the dominance of the blue LEDs as evidenced by the almost 83% of its total output in the 400-500 nm range with a peak at 454 nm. The classification of the 405nm and 420nm as UV is incorrect in the specification. The coordinates in the CIE diagram also indicate that this light has a strong blue visual look.
Figure 4 – Spectral Analysis of the GNC Bluray X
The overall spread and intensity over the 169 points of the testing grid are shown in Figure 5, at 24” and 30” from the bottom of the fixture. Peak values measured at 24” were 189.4 micromoles/m2/sec, and 123 micromoles/m2/sec at 30”.
Figure 5 GNC Bluray Light Intensity and Distribution at 24” and 30”
AI Blade Goral Grow – 21”
The AI Blade utilizes a linear cluster group configuration, with each linear cluster made up of 6 groups of 4 LEDs, as seen in Figure 6. The 21-inch model has 2 such linear clusters.
Figure 6. The LED arrangement in the AI Blade singe linear cluster (source: https://www.aquaillumination.com/wp-content/uploads/2022/11/ai-blade-ledLayout-coralGrow.webp)
Figure 7, shows the spectral analysis of the AI Blade Coral Grow as reported by the PGN100N spectrophotometer. The measurements were recorded at a distance of 23.25” from the fixture, as a single-point reading at the center of the LED fixture. The spectral analysis shows the dominance of the blue LEDs as evidenced by the almost 84.8% of its total output in the 400-500 nm range with a peak at 451 nm. The coordinates in the CIE diagram also indicate that this light has a strong blue visual look.
Figure 7 – Spectral Analysis of the AI Blade Coral Grow 21”
The overall spread and intensity over the 169 points of the testing grid are shown in Figure 8, at 24” and 30” from the bottom of the fixture. Peak values measured at 24” was 76 micromoles/m2/sec, and 49.7 micromoles/m2/sec at 30”.
Figure 8 AI Blade Coral Grow 21” Light Intensity and Distribution at 24” and 30”
Comparisons
Figure 9 below shows the comparison plot of the spectral distribution. Typical plots of spectral distribution (as shown earlier in the UPRtek reports) are usually individually scaled to the peak spectral value by setting it equal to 1. Since different LEDs may have different spectral peaks hence these plots do not provide an accurate comparison of the outputs at different wavelengths. To facilitate actual comparison of the output, it is more useful to scale the plots based on total PPFD rather than using a single spectral peak. In this paper, the spectral plots are scaled to a PPFD value of 175 for the purpose of comparison.
Figure 9. Spectrum comparisons scaled to equal PPFD of 175.
The actual PPFD measured at a distance of 23.25 from the center of the LED fixture and the grouping to create the lumped PFD over a range of wavelengths along with the UV and Far Red measurements are shown in Table 3. It should be noted that these are single-point measurements and can be heavily influenced by the optics used.
Table 3: PPFD measurements and lumped PFD in various wavelength bands
| LED | PPFD | PFD-UV(380-400 nm) | PFD – Blue(400-500 nm) | PFD- Green(500-600nm) | PFD-RED(600-700 nm) | PFD-FR(700-780nm) |
| Radion G6 | 172.0 | 3.048 | 120.7 | 28.95 | 22.39 | 1.487 |
| GNC Bluray X | 196.3 | 0.976 | 163.7 | 23.06 | 9.555 | 0.758 |
| AI Blade Grow 21” | 73.19 | 0.059 | 63.13 | 6.863 | 4.193 | 0.677 |
Each of the LED fixtures has a different power draw, as shown in Table 4. Generally, the more power consumed results in higher total light output, but the optics used in the fixture can change the distribution of the light.
Table 4: Power Comparison Table
| LED | Power (W) | Volts (V) | Amps (A) |
| Radion G6 XR30 PRO | 215.9 | 122.4 | 1.787 |
| GNC Bluray X | 140.6 | 121.6 | 1.173 |
| AI Blade Coral Grow 21” | 42.2 | 121.3 | 0.635 |
Other comparisons that can be made using the data, can look at the total and average PPFD over the 3ft area (169 pts) and 2ft area (81 pts). Since the intensity of the light is also a function of the power used, a metric using average PPFD/watt can be used to get a sense of the efficiency of the light by normalizing to the power input. This is presented in Table 5.
Table 5: Total and Average PPFD over the 3X3 ft and 2X2 ft area.
| LED | Distance | Total 3X3ft | Average – 3X3 ft | Av. PPFD /Watt | Total 2X2ft | Average – 2X2 ft | Av. PPFD /watt |
| Radion G6 XR30 PRO | 24” | 21115.4 | 124.9 | 0.58 | 12224.4 | 150.9 | 0.70 |
| 30” | 15618.5 | 92.4 | 0.43 | 8343.9 | 103.0 | 0.48 | |
| GNC Bluray X | 24” | 19285.4 | 114.1 | 0.81 | 11789.9 | 145.5 | 1.04 |
| 30” | 14628.4 | 86.5 | 0.62 | 8369 | 103.3 | 0.85 | |
| AI Blade Coral Grow 21” | 24” | 7149.2 | 42.3 | 1.0 | 4597 | 56.7 | 1.34 |
| 30” | 5658.3 | 33.4 | 0.79 | 3337.7 | 41.2 | 0.97 |
Conclusions
LED lighting has moved into the hobby mainstream and there are a lot of new choices available to the aquarist. Hopefully, this data will help the aquarist make an informed choice on what to expect from the individual LED fixtures and how best to utilize them to achieve the desired coverage and light intensity. In my experience, a target of approximately 100 micromoles/m2/sec at the bottom of the tank will provide enough of a light gradient to satisfy a wide range of corals. Multiple fixtures will provide regions of overlapping light distributions which provide an additive effect thereby increasing the light intensity and area covered.
