Analyzing Reflectors: Part 3

In Part I and II of this series [1, 2], we presented the data on 400W single ended mogul reflectors, designed primarily to be retrofit into existing canopies, and 250W Double ended reflector fixtures. This article continues in a similar vein and presents the data and analysis of several additional reflectors that we were able to obtain since the last set of tests.

Table 1: Listing of the Reflectors Tested
Reflector Ballast Lamp
PFO Illuminator Magnetic Ballast (M59) Ushio 400W 10000K
SuperSun IV – Sunlight Supply Magnetic Ballast (M59) Ushio 400W 10000K
Reef Optix I – Sunlight Supply Magnetic Ballast (M59) Ushio 400W 10000K
Small Diamond Light PFO HQI Ballast (M81) Vion 250W 10000K
Regent DIY 150W Double Ended Reliable Ballast (electronic) AB 150W 10000K
Giesemann 250W Nova II Giesemann Ballast (electronic) AB 250W 10000K
Giesemann 150W Nova II Giesemann Ballast (electronic) AB 150W 10000K

PFO’s Illuminator and Sunlight Supply’s SuperSun are designed primarily for horticulture use, but given that we tested the Diamond Lighting’s Lumen Arc III which is also a reflector designed for horticulture applications, we felt it would be interesting to test a few other horticulture reflectors. Diamond Light also makes a smaller reflector (called LA3) which is more suited for 250W single ended mogul lamps (it does not accommodate the 400W lamps as they are too long to fit in this reflector). The small Diamond Light reflector’s results are also shown here. Unfortunately, when this reflector was tested the only available 250W lamp on hand was a Vion 250W lamp (not the best lamp in its class and is no longer being sold). So this data cannot be directly compared to the 10000K lamps and reflector systems, however, the % distribution plots of this reflector would provide useful data for comparison purposes.

The two Giesemann Nova II fixtures are also a choice available to the discerning aquarist especially those interested in aesthetically pleasing designs and good quality, and these reflectors are also tested here.

As avid DIY’ers ourselves, we also explored a cheap version of the 150W double ended reflector system made by retrofitting a Regent 500W Halogen lamp fixture. The allure of this fixture is the fact that it can be easily purchased at Lowe’s or Home Depot for about $10, and with a small retrofit of replacing the halogen sockets with the sockets for the 150W double ended lamps, one could make a very cheap reflector for about $20 and change.


The basic methodology and experimental setup is identical to the one used in the previous set of articles (part I and II, references [1] and [2]). The data is also presented in an identical manner with plots for light dispersion for each reflector at distances of 6″, 9″ and 12″ from the center of the lamp. This article is intended to be a continuation of the previous articles and hence should be read in conjunction with the other two articles.

Reflector Data And Analysis

The data plots for each reflector at the distances 6″, 9″, and 12″ are plotted as a surface graph, top view graph, and a % distribution graph to illustrate the intensity and spread at different points on the measuring grid. Table 2 below shows the list of figures associated with each reflector.

Table 2: List Of Figures Associated With Each Reflector
Reflector Figures
PFO Illuminator Figs. 1-3
SuperSun IV – Sunlight Supply Figs. 4-6
Reef Optix I – Sunlight Supply Figs. 7-9
Small Diamond Light Figs. 10-12
Regent DIY 150W Double Ended Figs. 13-15
Gieseman 150W Nova II Figs. 16-18
Gieseman 250W Nova II Figs. 19-21

One of the measures of a reflector performance could be its ability to direct light into the aquarium. A reflector’s total incident light upon a surface of a given area is representative of the performance of a reflector. It is computed by adding up all the measurements taken at the discrete points within the region. It demonstrates how much light the reflector is able to focus downward when compared to other reflectors with similar operating conditions (same ballast and lamp). While it can be argued that adding all the PPFD values is technically not a valid measure as per the definition of PPFD (since PPFD is defined as μEinstein/m2/sec), it can be used to provide a metric for reflector performance. Further summing over the data points on a given area can easily be used to compute the average, if so desired. Since the area under consideration is the same for all reflectors, we can just as well use the sum of the PPFD values distributed over this area (169 data points) instead of an average as a performance metric.

Table 3: Total Incident PPFD on a given Surface area.
Reflector: Distance: Total Incident Light Maximum PPFD
3×3 Area 2×2 Area 1×1 Area
PFO Illuminator 6″ 45388 43285 31140 2147
9″ 44385 37609 21809 1270
12″ 39631 30759 14603 755
SuperSun IV – Sunlight Supply 6″ 44585 43867 32103 2150
9″ 44326 39437 22892 1285
12″ 41449 33108 16279 860
Reef Optix I – Sunlight Supply 6″ 44223 42290 30168 2547
9″ 41082 35476 22486 1793
12″ 39887 32318 18703 1317
Small Diamond Light 6″ 27308 26700 21857 1698
9″ 24705 22616 15519 1000
12″ 23837 20854 12185 685
Regent DIY 150W Double Ended 6″ 17046 17046 14985 1706
9″ 16058 16058 10854 815
12″ 13854 13854 7717 465
Giesemann 250W Nova II 6″ 32085 31875 28454 3360
9″ 31479 30400 20502 1513
12″ 30618 26931 16571 887
Giesemann 150W Nova II 6″ 15715 15596 14048 1683
9″ 15404 14722 10159 754
12″ 14901 12898 7144 418

As can be seen from this data, the 2 horticulture reflectors (PFO Illuminator and Sunlight Supply’s Super Sun IV) and the Reef Optix are very similar in performance. We have found that reflectors with the ends closed tend to perform better. The Giesemann Nova II fixtures, while very aesthetic and thoroughly designed, could benefit specifically from improved reflector design.

In addition to knowing how much light is incident on a given area, we could also look at how much loss of light occurs on a given area when moving the lamp and reflector higher. Table 4, presents the % of light lost on a specified area as one moves the lamp/reflector from 6″ to 12″ above the surface. A higher % loss would indicate that the reflector is creating a larger spread.

Table 4: Percent of PPFD lost from 6″ to 12″ from the lamp
Reflector 3×3′ Area 2×2′ Area 1×1′ Area
PFO Illuminator 13 30 53
SuperSun IV – Sunlight Supply 7 25 50
Reef Optix I – Sunlight Supply 10 24 38
Small Diamond Light 13 22 44
Regent DIY 150W Double Ended 19 19 49
Giesemann 250W Nova II 5 16 42
Giesemann 150W Nova II 5 50 49

Another metric to analyze reflector performance could be to determine the area coverage of a specified amount of light. Although it is difficult to determine exactly what this specified minimum PPFD values should be, we have chosen a cut off of 500 PPFD and present the area coverage plots of each of the reflectors in Figures 22,23, and 24.



Figure 22


Figure 23


Figure 24


Figure 1: PFO Illuminator



Figure 2: PFO Illuminator TOP View


Figure 3: PFO Illuminator – %


Figure 4: Sunlight Supply – SuperSun IV


Figure 5: Sunlight Supply – SuperSun IV Top View



Figure 6: Sunlight Supply – SuperSun IV %


Figure 7: Sunlight Supply – Reef Optix I


Figure 8: Sunlight Supply – Reef Optix I Top View


Figure 9: Sunlight Supply – Reef Optix %


Figure 10: Small Diamond Light – LA3


Figure 11: Small Diamond Light – Top View


Figure 12: Small Diamond Light – %


Figure 13: Regent DIY


Figure 14: Regent DIY – Top View


Figure 15: Regent DIY – %


Figure 16: Giesemann Nova II 150W


Figure 17: Giesemann Nova II 150W – Top View


Figure 18: Giesemann Nova II 150W – %


Figure 19: Giesemann Nova II 250W – PAR


Figure 20: Giesemann Nova II 250W – Top View


Figure 21: Giesemann Nova II 250W – %


Figure 22: 500 PPFD Cuttoff for 400W Reflectors


Figure 23: 500 PPFD Cutoff for 250W Reflectors


Figure 24: 500 PPFD Cutoff – 150W Reflectors


This article is the 3rd in this series and presents the data and a brief analysis of several additional commercially available reflectors. The data provided shows clearly the differences between the reflectors, and can provide the reader with useful data on the light distribution patterns and shapes, which in turn can be used for purposes of aquascaping and placement of corals.


We would like to thank several people whose help made this study possible. They were kind enough to provide us with lamps, reflectors and ballasts for testing: Patrick at PFO Lighting, Brad at Sunlight Supply, Phil at Xenia Inc. for the Giesemann fixtures, Shane Graber for the use of his small diamond light reflector, and Brian at


  1. Joshi, S. and Marks, Timothy. 2003. Analyzing Reflectors: Part I – Mogul Reflectors
  2. Joshi, S. and Marks, Timothy. 2003. Analyzing Reflectors: Part II – Mogul Reflectors
  Advanced Aquarist
Sanjay Joshi

 Sanjay Joshi

  (43 articles)

Sanjay Joshi in real life is a Professor of Industrial and Manufacturing Engineering at Penn State University. He has been a reef addict since 1992, and currently keeps several reef aquariums at home including a 500G SPS coral dominated reef. He also co-manages the 500G aquarium at Penn State. He has published several articles in magazines such as Marine Fish and Reef Annual, Aquarium Frontiers, Aquarium Fish, and Advanced Aquarist. In addition, he has been an invited speaker at several marine aquarium society meetings in the US and Europe. He received the MASNA award in 2006, for his contributions to the marine aquarium hobby.

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