Introduction and Background


When initially starting this adventure, the goal I had in mind was to investigate lamps that would be suitable for use in my tank when the time came to change metal halide lamps. At the time I found little information available on the 250-watt single-ended (SE) metal halide (MH) lamps that I was using. Prior to actually laying out the funds to buy the same type of lamps again, it seemed reasonable to research a wide variety of products that were available on the market. That way, I could be certain that the product that I purchased best fit the needs of my tank.

In the beginning, some fellow reef enthusiasts assisted my search for suitable replacement lamps. A few friends lent me some of their extra lamps, and I was also able to borrow a PAR meter from another associate. After using the new equipment, I took readings and shared my findings by posting an "innocent" picture or two on Reef Central. Thereafter, my project took on a life of its own. Soon, people were e-mailing me and asking me to post more information on other lamps. People offered to send me a lamp or two to test. While testing more lamps, I found some ways of testing to be better than others. I found myself with results that left me with questions that needed to be answered. I realized that I had lighting questions that I needed clarified so that I could better understand the results that I was seeing and, in turn, have the ability to explain my findings to others. I wondered about the reasoning as to why measuring photosynthetically active radiation (PAR) was better than measuring lux. In an effort to seek a fuller understanding, I spent a great deal of time researching, testing and discussing basic lighting with people more knowledgeable than I. This resulted in a massive thread on Reef Central encompassing some 50-odd pages, and boasting 1300 posts, wherein I discussed all of the lamps that I tested, along with my notations regarding each product and my final test results. Such a thread is definitely a large undertaking for any aquarist to comprehend. I decided to write the present article to summarize my findings in an effort to help reef aquarists better understand what I tested, and to share my results.

What Was Tested


I tested just about every lamp and ballast that I could get my hands on during the testing time. Whatever I received made it onto the final list. A total of 21 lamps and 8 ballasts were used, as shown in Table 1 below. Almost all of the lamps were tested on every ballast. I had to return a few lamps (and one ballast) to the person who lent them to me, as they needed to be used on the person's tank. Therefore, not every combination was tested. Still, each ballast/lamp was tested against enough lamps/ballasts that their performance tendencies are readily seen; whether being judged on its own or against other similar equipment.

Table 1 Lamps and Ballasts Tested
Lamps Tested
Ballasts Used
Aqualine Buske 13000K
PFO 13000K
ARO (Hellolights) Electronic Ballast
AquaConnect 14000K
Radium
CoralVue Electronic Ballast
Blueline 10000K
Sunburst 12000K
Blueline E-Ballast Electronic Ballast
Blueline Super White
Sun Aquatics 10000K
EVC Ballast
CoralVue 10000K
Sun Aquatics 14000K
IceCap Electronic Ballast
CoralVue 12000K
Sun Aquatics 20000K
PFO HQI Ballast
CoralVue 15000K
Ushio 10000K
PFO Standard Ballast
CoralVue 20000K
XM 10000K
Reef Fanatic Ballast
EVC 10000K
XM 15000K
 
Hamilton 14K
XM 20000K
 
Iwasaki 6500K
 
 

Ballasts appeared to operate the same regardless of how long they had been used. I found no difference between one that was fresh out of the box and one that had been run for months, or even years. That led me to believe that there was no break-in period for metal halide ballasts.

How These Tests Were Conducted


I should state up front that I am a hobbyist; I'm not an electrical engineer, nor am I involved with the manufacture of lighting equipment. I conducted these tests solely to satisfy my own curiosity, out of my enthusiasm for the hobby. When these tests were started almost no information was available for 250-watt SE metal halide lamps. With that said, I tried to get as much pertinent information as I could to answer my question on how different 250-watt SE metal halide lamps performed. In turn, I wanted to share my understandings with other hobbyists so that we could make a better, more informed decision about what types of lighting we purchase to support our systems. As a side note, all of the lamps that I tested were burned in for at least 120-150 hours before being tested. Additionally, all lamps, excluding the Ushio, AB and Blueline Super White, were new at the time of testing. The remaining lamps had roughly six months of use on them (approximately 1600 hours).

It's interesting to note that during the first 100 hours of burn-in time, the halides in the arc tube settle. I found that during the first 100 hours of burn-in time, the amount of light emitted from the lamp was higher (by approximately 10% - 20%) than it was after breaking-in the lamp. It seems reasonable to conclude that the level of light emission stabilizes over time. This is an important note for the reefkeeper when changing lamps. It has been my experience that, in most instances, the measurable output of lamps after a 10-14 month period is nearly 10-20% less than their initial emission. This leads me to believe that if the reefkeeper does not carefully acclimate his corals to new lighting variables, then the lower output of the older lamps, coupled with the higher (albeit temporarily) output of the new lamps, enhances the possibility of a coral bleaching event. Is it no wonder that people so often lose some of their prized acroporids to bleaching after completing a lamp swap?

After a few short tests that were done over my tank (results on this RC thread), it was painfully obvious that a separate environment to test the lamps was needed. This environment would need to be able to produce repeatable results. After much time, and many conversations with other people in the lighting industry, a solution was found. What I wanted was the raw output from the lamp only. Reflector efficiency varies greatly from one product to the other and many people use different reflectors and/or material to get extra output from the lamp, so I decided not to include any reflectors in my testing, as the results couldn't be universally applied if the variable of an assortment of reflectors was involved.

Testing box.

I finally settled on a 2' x 2' x 2' square box (seen above). Its inside was painted flat black to minimize the amount of light reflected back to the sensor. The mogul socket was mounted horizontally, approximately 5" from the ceiling of the box. The quantum sensor (a sensor used to measure PAR) was placed 8" below the center of the arc tube. I chose 8" because this seemed to be a common distance that people keep their MH lamps from the water's surface. To minimize voltage spikes and aberrations, a voltage regulator was used on power from the wall's electrical socket. A watt meter was plugged into the voltage regulator and the ballast plugged into the watt meter.

All lamps, before testing, were powered on and left to burn for at least 20 minutes before any measurements were performed, in order to allow the bulb's output to stabilize. After 20 minutes the sensor was turned on and time was given for a stable reading to be displayed from the meter. Some time (between 2-5 minutes) was given for the reading on the meter to stabilize for at least 30 seconds with no movement. At that time, readings were recorded.

Equipment Used:

  • Apogee instruments QMSS-ELEC quantum meter with sensor: calibrated for electric lamps

  • Apogee instruments leveling plate for the sensor

  • APC Line-R 600 voltage regulator/power conditioner

  • Electronic educational devices - Watts Up? power analyzer/watt meter

  • Nikon 995 digital camera used with tripod for pictures

  • BK Precision 530 multimeter

PAR vs LUX


Many people asked why I used PAR (Photosynthetic Active Radiation) as a way of measuring the lamps as opposed to lux (a photography and media term used to measure light values). Also, many people wanted to know if their lux measurements could be translated into PAR values. In an effort to be as concise as possible on this topic, I'll state that PAR measurement is useful for a number of reasons, the primary one being that it measures the band of light (400nm-700nm) where photosynthesis can occur. A secondary reason is that the light is measured uniformly. Lux readings are geared toward the way humans see light, so greens and yellows are given a higher weight than purples and blues. PAR readings measure nearly the whole visible light spectrum, 400nm-700nm, evenly.

Here are two graphs from Li-Cor, a manufacturer of instrumentation for environmental research. They show how accurate the company's sensors are in reference to an "ideal" curve. In our case, we are interested only in the curve represented by the dotted line.

A graph of how lux is measured:

Graph courtesy of Li-Cor.

A graph of how PAR is measured:

Graph courtesy of Li-Cor.

The graphs clearly show that PAR is a more accurate way to measure lighting for a tank housing photosynthetic organisms.

The graph also shows that getting a lux reading from one lamp is good for comparing it only to the same lamp, or to another lamp with the same spectral plot. Yet, a lux reading from a 6500K lamp could not be equally compared to the lux reading of a 20,000K lamp.

Apogee Sensor Accuracy


The PAR (or quantum) sensor and meter I used are made by Apogee Instruments. They make a reasonably priced sensor that a hobbyist can afford (i.e., under $300). Sanjay Joshi, in his lamp testing, has used a quantum sensor made by the Li-Cor company that costs well over $1000. Naturally, numerous questions were raised about the accuracy of the Apogee sensor used in the test.

The margin of error needed to be considered regarding this sensor. I contacted Apogee and discussed this with a representative, who agreed to send to me two Li-Cor sensors that the company uses for in-house testing. The sensors were first calibrated by Apogee and then shipped to me. After I received the Li-Cor sensors, I took measurements. Two Li-Cor sensors were sent to take measurements with, and to have an average baseline to work from so I could compare them to the Apogee. One measurement with each Li-Cor sensor was taken, and then the two were averaged to produce a value. While the lamp was still lit, a reading from the Apogee sensor was taken and compared to those obtained by the Li-Cor sensors. The table below shows the margin of error the Apogee had when compared to the Li-Cor. Also shown is an adjustment factor. If this factor is applied to the Apogee reading (take the initial reading from the Apogee and multiply it by the adjustment factor), it should correct for any deficiencies of the sensor. All lamps have a slightly different spectral curve, so the error is different for each lamp.

Table 2 - Apogee Sensor Accuracy
Lamp
Adj. factor
Error %
AB10K
1.042700
4.27
XM10K
1.000102
0.01
XM20K
1.054623
5.46
Radium
1.020256
2.03
CV10K
1.014444
1.45
Ushio10K
1.022647
2.26
PFO13K
1.066219
6.62
Iwasaki
1.004403
4.40
BLSW
1.035931
3.59
SUN10K
1.041306
4.13
CV15k
1.062583
6.26
CV20K
1.031709
3.17
BL10K
1.020969
2.10
HM14K
1.041438
4.14
AQ14K
1.027771
2.77
SUNBRST 14K
1.025221
2.52
CV12K
1.076923
7.69
SUN14K
1.026404
2.64

As the chart shows, for such a low price, the sensor is very accurate. On average, it deviates from the Li-Cor sensor by only 3.64%. After taking these readings I felt that, for hobbyists' purposes, the reading from the Apogee sensor was more than sufficient.

Lamp Heat Due to Ballasts


Many people, including myself, have always wondered how much heat is generated from adding metal halide lamps over a tank. I've also wondered how much of a difference fans make in keeping the lamp's heat from impacting the tank's water temperature. To answer these questions, I took measurements and found that different ballasts do vary the amount of heat produced by the lamp.

Temperature measurements were taken the same distance from the lamp as the light sensor was placed - 8". The ballast was turned on with a fan above the lamp, effectively pulling the heat out. After 35 minutes, the temperature 8" from the lamp was taken. To determine the contribution of ventilation to heat generation, we then turned off the fan and, after 10 minutes more (for a total trial of 45 minutes), measured and recorded the temperature again. Ambient room temperature during all the testing was 70°F. The results are found in Table 3 below.

Table 3
Ballast
Lamp
0 Min
35 Min
45 Min/No Fan
PFO Standard
Ushio
70.0°F
83.2°F
90.1°F
PFO HQI
Ushio
70.3°F
87.5°F
97.2°F
eballast
Ushio
70.5°F
81.4°F
89.5°F
Icecap
Ushio
70.1°F
78.6°F
85.2°F
CoralVue
Ushio
70.3°F
82.1°F
90.6°F
ARO
Ushio
70.2°F
79.6°F
88.3°F

It seems quite obvious that heat from the lamp can play a significant role in heating the water in the tank. After 45 minutes, the temperature with a fan was approximately seven degrees less than it was with no fan. In the case of the PFO HQI ballast, the ambient temperature in the test box rose almost 27 degrees Fahrenheit when not using a fan to vent excess heat! Proper ventilation, therefore, is a must in any lighting fixture/canopy.

Actual Power to the Lamp


Manufacturers of many of the new electronic ballasts report that they are better suited than magnetic ballasts to power aquarium metal halide lamps due to their sophisticated internal circuitry. In order to test this claim I decided to take some measurements on the wire between the ballast and lamp. The results are given below. While I'm unsure if these results speak better of electronic or magnetic ballasts, the interesting thing to note is that the electronic ballasts varied in their ability to deliver power to the lamp. These two specific lamps were chosen because they were ones that I could track down the power and current specifications as released by the manufacturer.

Voltage measurements were taken using a BK 5390 Multimeter. Current measurements are reflected in TRMS. (RMS stands for Root Mean Square, a technique used to measure AC voltages. True RMS, or TRMS, takes harmonic distortion into account to accurately measure non-sinusoidal AC voltage and current waveforms. On a sinusoidal waveform, RMS and TRMS are the same; therefore, TRMS is advantageous when measurements of non-sinusoidal AC waveforms are required.) The electronic ballasts seem to use the DC sine wave, so both AC and AC+DC measurements were taken. All measurements were taken on the wire between the ballast and the lamp. All ballasts were plugged into a PFO style plug that connected to the mogul socket for the lamp. Measurements were taken where the plug connects to the socket, so all ballasts were measured using the same wire. The lamps were first ignited by the ballast, then left to burn for 20 minutes. At that time, measurements were taken. The results are shown in Table 4 below.

The boldfaced first line in the table below shows the manufacturer's specifications of the lamp. Following are the readings taken while running the lamp on different ballasts. The Standard PFO ballast would not drive or start the Radium lamp, so no information is given for this combination.

Table 4 Power Profile of Ballasts Tested
Lamp Ballast
AC AMP
AC+DC AMP
Volts
kHz
Line watts
Line volts
Radium SPEC
2.80
2.80
95-100
 
 
 
Radium HQI
2.63
2.63
113.50
59.98 Hz
308
117
Radium ARO
3.20
4.79
112.37
76.80
249
117
Radium eballast
2.21
1.95
110.65
80.73
242
121
Radium IceCap
3.20
4.58
109.60
70.47
248
119
Radium CV
2.29
2.01
109.63
67.52
264
119
Radium ReefFanatic
2.28
2.80
131.90
42.03
246
119
Radium EVC
2.37
2.88
115.80
44.68
247
119
 
Ushio SPEC
3.00
3.00
100.00
 
 
 
Ushio HQI
2.43
2.43
133.41
59.98Hz
339
118
Ushio ARO
2.94
4.64
125.43
77.95
249
119
Ushio eballast
1.80
1.59
123.04
86.68
243
119
Ushio IceCap
2.87
4.40
127.78
73.43
254
119
Ushio CV
1.84
1.62
125.39
72.84
254
121
Ushio ReefFanatic
2.62
3.20
116
44.06
246
119
Ushio EVC
2.10
2.42
132.20
41.98
246
120
Ushio Standard
2.11
2.11
129.34
59.98Hz
273
118

The Meat of it All: Testing the Lamps


Table 5 below represents the main thrust of the testing that was done. Each lamp was tested on the ballasts available to me at the time. I was asked to return the CoralVue ballast a few months after testing, so fewer lamps are shown on that ballast than on the others. I received quite a few different lamps after returning this ballast to the manufacturer. The measurements for all of the ballast/lamp combos tested are shown below. PAR is the reading from the Apogee sensor after 20 minutes of lamp illumination. The columns marked "Watts" and "Amps" represent the power drawn by the ballast from the wall's electrical socket after being passed through the voltage regulator. Generally speaking, ballasts need to produce an initially high current pulse to ignite the lamp, and in some cases this shows up as a high amperage draw that is captured under "Max Amps."

This series of charts demonstrate in PAR the amount of light available for photosynthesis. In general, we are looking for higher PAR values. The data are sorted by PAR value ranking.

Table 5
ARO (Hellolights) Electronic Ballast:
Lamp
PAR
Watts
MaxWatts
Amps
MaxAmp
605
250
253
2.11
2.19
526
250
251
2.16
2.37
465
250
254
2.16
2.20
463
249
256
2.16
2.19
461
248
256
2.14
2.23
434
252
254
2.15
2.51
408
251
269
2.14
2.61
391
253
258
2.23
2.33
360
249
251
2.11
2.15
338
249
253
2.17
2.63
327
249
252
2.18
2.23
302
250
270
2.18
2.50
286
249
265
2.16
2.55
270
250
253
2.16
2.41
259
249
255
2.15
2.37
258
250
273
2.17
2.48
253
246
250
2.14
2.19
243
250
252
2.16
2.22
227
246
278
2.17
2.53
206
251
252
2.16
2.19
171
252
256
2.2
2.27
CoralVue Electronic Ballast:
Lamp
PAR
Watts
MaxWatts
Amps
MaxAmp
569
247
266
2.00
2.36
541
257
270
2.12
2.50
480
252
270
2.02
2.20
430
262
265
2.10
2.13
368
224
268
1.80
2.39
363
255
265
2.08
2.38
363
258
268
2.09
2.49
337
260
269
2.13
2.89
316
260
265
2.09
2.22
311
260
265
2.10
2.16
265
256
261
2.09
2.12
257
248
269
2.01
2.19
203
244
268
1.97
2.17
Blueline E-Ballast Electronic Ballast:
Lamp
PAR
Watts
MaxWatts
Amps
MaxAmp
558
244
247
1.99
2.14
521
243
244
2.00
2.03
474
246
250
1.99
2.11
468
245
249
1.99
2.05
468
244
245
1.99
2.00
430
245
247
2.00
2.03
428
246
249
1.99
2.09
390
246
247
2.00
2.03
343
243
244
1.98
2.00
341
242
243
1.95
1.96
340
242
244
1.93
2.00
323
242
243
1.95
2.05
266
240
241
1.93
1.95
261
240
242
1.93
2.71
243
242
268
1.98
2.52
238
242
243
1.95
2.21
234
240
240
1.92
2.64
228
244
250
1.99
2.12
194
248
249
2.0
2.24
178
244
245
1.97
1.99
EVC Ballast:
Lamp
PAR
Watts
MaxWatts
Amps
MaxAmp
559
246
249
2.03
2.80
517
247
250
2.03
2.87
438
250
254
2.03
2.1
425
247
248
2.01
3.29
423
247
249
2.00
3.20
412
246
248
2.01
2.08
394
247
248
2.02
3.65
350
246
250
2.01
2.06
294
247
248
2.03
2.59
291
246
251
2.01
3.66
290
247
248
1.98
2.37
261
246
248
2.00
3.33
257
246
294
1.97
2.02
254
246
247
2.00
2.59
241
247
248
2.01
2.14
211
252
256
2.07
2.12
184
246
248
2.00
2.40
IceCap Electronic Ballast:
Lamp
PAR
Watts
MaxWatts
Amps
MaxAmp
651
252
275
2.17
2.45
530
252
254
2.20
2.82
494
252
255
2.14
3.86
494
252
254
2.15
2.83
492
252
254
2.15
2.96
422
254
257
2.17
2.30
414
252
258
2.19
3.41
406
252
264
2.17
2.32
387
250
251
2.17
2.46
352
251
252
2.17
2.29
330
252
275
2.19
3.56
307
251
253
2.20
2.25
304
253
284
2.17
2.61
270
252
301
2.17
2.81
263
248
250
2.18
3.68
259
251
253
2.17
3.32
253
251
308
2.18
2.79
242
251
252
2.20
3.85
227
251
268
2.18
2.86
224
247
249
2.20
3.00
187
252
254
2.17
2.83
PFO HQI Ballast:
Lamp
PAR
Watts
MaxWatts
Amps
MaxAmp
950
355
384
3.02
4.79
835
340
341
2.93
4.07
702
349
359
3.00
5.72
700
345
350
2.99
3.87
699
342
346
2.95
3.36
659
341
349
2.96
4.55
617
349
360
3.00
7.42
457
333
335
2.87
3.25
453
311
313
2.85
4.74
420
317
361
2.79
6.86
395
311
315
2.75
3.28
378
311
698
2.79
14.27
355
321
330
2.79
5.18
336
317
322
2.76
4.55
328
310
314
2.73
4.45
318
312
847
2.79
16.33
314
327
337
2.85
3.94
314
327
490
2.92
8.69
308
311
418
2.76
8.08
292
310
385
2.83
10.03
232
292
393
2.81
10.65
PFO Standard Ballast:
Lamp
PAR
Watts
MaxWatts
Amps
MaxAmp
691
286
331
2.53
6.86
600
268
269
2.47
3.39
566
301
303
2.64
3.81
514
273
274
2.49
5.47
512
271
278
2.50
3.12
510
270
277
2.51
2.69
485
284
285
2.53
4.57
324
231
233
2.32
4.03
309
269
269
2.51
6.01
283
231
232
2.38
6.81
275
226
261
2.30
7.93
264
265
267
2.55
7.42
248
257
258
2.50
6.80
242
227
239
2.35
4.14
242
285
285
2.57
3.75
228
224
228
2.32
4.08
228
212
274
2.33
8.29
214
219
220
2.30
7.12
190
230
230
2.38
3.54
148
198
199
2.25
6.11
Reef Fanatic Ballast:
Lamp
PAR
Watts
MaxWatts
Amps
MaxAmp
571
247
248
2.03
2.77
523
247
248
2.03
3.30
454
246
247
2.00
3.75
441
247
249
2.03
2.62
420
246
249
1.98
3.68
417
247
248
2.01
3.44
383
246
248
2.04
2.67
350
247
248
2.03
2.60
294
246
247
1.94
2.70
283
247
250
2.01
2.21
257
246
247
2.01
2.15
252
246
248
2.00
2.92
246
246
334
2.03
3.31
239
246
247
2.00
2.02
209
251
253
2.07
2.09
185
246
248
2.00
3.35
Legend:
AB13K = Aqualine Buske (AB) 13000K, (also labeled 10000K in some stores, but they are the same lamp), AQ14K = Aquaconnect 14K, BL10K = Blue Line 10000K (also called 10K+), BLSW = Blue Line Super White MH, CV10K = Coralvue 10000K, CV15K = Coralvue 15000K, CV20K = Coralvue 20000K, EVC10K = EVC Technologies 10000K, HM14K = Hamilton 14000K, Iwasaki = Iwasaki 6500K MH, PFO13K = PFO 13000K, Radium - Radium also called Radium 20000K, SBURST12K = Sunburst 12000K, SUN10K= Sun Aquatics 10000K, SUN20K = Sun Aquatics 20000k, SUN14K = Sun Aquatics 14000K, Ushio = Ushio 10000K, XM10K = XM10000K MH, XM20K = XM20000K MH

PAR values as an average.

A graph showing the average PAR value for each lamp from all the ballasts.

Bulb Appearance


The picture on the left is with actinics off. The picture in
the middle is with two 140-watt URI VHO actinics on.

AB13K: Aqualine Buske 13000K

AQ14K: AquaConnect 14000K

BL10K: Blueline 10000K

BLSW: Blueline Super White

CV10K: CoralVue 10000K

CV12K: CoralVue 12000K

CV15K: CoralVue 15000K

CV20K: CoralVue 20000K

EVC10K: EVC 10000K

HM14K: Hamilton 14000K

Iwasaki: Iwasaki 6500K

PFO 13K: PFO 13000K

Radium: Radium 20000K

SBURST12K: Sunburst 12000K

SUN10K: Sun Aquatics 10000K

SUN14K: Sun Aquatics 14000K

SUN20K: Sun Aquatics 20000K

Ushio: Ushio 10000K

XM10K: XM 10000K

XM20K: XM 20000K

Conclusions


When reading through all these data, the first thing to become apparent is that they are voluminous. Because of this, we need to have a goal in mind when viewing the data. The information can mean different things to different people. Looking at the data to simply find the best lamp will not yield good results. Rather, think long and hard about what you are keeping, what color lamp you enjoy, and what kind of ballast you are looking for.

In my case, I did change my lighting system after doing these tests. After starting the testing, I wanted to find a lamp/ballast combination that put out as much PAR as the Ushio/HQI ballast combination I had been using. Finally, I settled on the combination of the XM10K lamp and the Icecap electronic ballast. The Ushio on an HQI ballast still puts out about 15% more PAR than the XM10K running on an Icecap, but I felt that it was close enough. After making the switch my colors and growth were just about the same as before. The main differences are less heat produced and less electricity consumed.

Someone else's goal might be different, but it will make your life much easier if you have an idea of what you are trying to achieve when interpreting the data.

Acknowledgements


I would like to thank PFO Lighting, DIY Reef, Premium Aquatics, HelloLights, Ocean Encounters, Icecap, Champion Lighting, Sun Aquatics, Sanjay Joshi and all the hobbyists who lent me lamps and let me ask them questions about how to do these tests. Without all of you, I never would have been able to gather this information and pass it on.



If you have any questions about this article, please visit my author forum on Reef Central.




Reefkeeping Magazine™ Reef Central, LLC-Copyright © 2008

Testing 250-watt Single-ended Metal Halide Lamps and Ballasts by Joe Burger - Reefkeeping.com