Some reflector testing
by
, 03-25-2010 at 07:29 PM (6314 Views)
Back in mid-2009, I did some testing because of the variety of reflectors people were asking about. This entry will be about the Lumenbright series as well as the LumenMax Elite.
From this angle, you can see how thick (tall) each reflector is. After all, how much room you have in the canopy dictates what fits and what doesn't.
I set up a hanger in the kitchen, centering the reflector's bulb in the middle of a 9-tile grid. The grid is 36" x 36". The PAR sensor was affixed to the floor to keep it pointing straight up. This picture was taken with a flash to show the full area. Each reflector was hung so the bottom edge was 14.5" off the tile floor.
The ballast is a brand new 400w Lumatek ballast with a brand new Radium bulb.
All pictures were taken in Manual mode so it would be comparable.
The first test was with the Lumenbright Large.
The second test was the Lumenbright Mini.
The third test was the Lumenbright Mini Wide
And the final test was the LumenMax Elite.
My thoughts after the testing:
Last July, BigJay came over with a bunch of ballasts, a LumenMax reflector, and a 14,000K AquaMaxx bulb. He wanted to do some PAR testing to see if the ballasts made a difference between the old-style ballasts like my older IceCap eballast vs the newer prettier kind now available. He also had an ARO that looked identical to the IceCap (old style).
- The largest reflector didn't have as much PAR as one might expect, but the light has to travel further from the bulb to the reflective surfaces, and bounce down to the sensor.
- The Mini and the Mini Wide were more powerful. I would probably want to raise them up higher.
- The LumenMax Elite was the weakest performer of the four reflectors, even though the ballast and bulbs were the same. Perhaps this is a better choice for a shallower canopy.
- All four reflectors did light up the 36" x 36" grid nicely, more than the pictures indicate. The camera picked up on the hot spot each time, and using a flash would have been misleading.
- It is absolutely true that you can not tell the Mini from the Mini-Wide reflector when viewing them side by side. I stared at the facets to see how it is any wider, and it isn't apparent. The difference in PAR does lead one to consider that the light isn't as intense dead center and is being spread out a bit more. Since it did put out a little more light than the Large, I could imagine that it would benefit wider tanks that need more reflectors where a Large doesn't have the spread. For example, if the display was 48" front to back, two Mini-Wides would be a better choice than a Large.
The LumenMax reflector was set up from the 24" x 24" target. It held the Single Ended 14,000K mogul bulb, socket end up (on the graphs below), and the tempered glass panel was in place. The LumenMax reflector uses a hammer-tone dimpled surface.
Each measurement was taken 17" from the sensor's tip to the bulb. The center point was of course the strongest. As you can see, the top row (in three of the four graphs), the number was lower because that is where the mogul socket is, and is the point of least reflectivity. The bulb's tip, as depicted in the lightbulb orientation in the graph below, was more intense as there was an angled panel of the dimpled reflector behind it to provide more light.
If this particular reflector is installed over a reef tank, I would recommend that it be placed perpendicular over the reef so the cord and socket are near the back of the tank were light typically isn't needed. This way you get good spread across the reef, and it lights the front half of the tank well. The back panel usually doesn't need that type of lighting, as we rarely focus upon that area when stocking our tanks with corals.
The final graph (lower right in the image below) shows the measurements taken with the Lumenbright Mini Wide, with the tip of the sensor 19" from the bulb. The tempered glass was in place. The socket had no effect this time due to the bowl shape of the reflector, providing an overall bright field of light at the four corners of the compass, as expected. This reflector was 100 PAR stronger in the center point. The ballast and bulb used were the same used with the LumenMax reflector (bottom left in the image below). One thing to note was the cord from ballast to reflector was shorter, as no proprietary cord was necessary, but the bulb was a full 2" further away than the other tests. One might conclude that a shortened cord would improve PAR due to less resistance, but with the bulb further away, it would be reasonable to expect the numbers to even out. In this case, the PAR was 100 more with the bulb being further from the target spot.
Another small group of factoids:
- IceCap - old style - Watts used according to the Kilowatt meter: 252
- ARO - old style - Watts used according to the Kilowatt meter: 250
- IceCap - new style - Watts used according to the Kilowatt meter: 264
- Both the old-style ballast were pretty hot to the touch, and had a slight hum.
- The new style ballast was dead silent, and only a little warm even after running for 30 minutes.
As many of your know, I really like the Lumenbright pendant reflectors. If you were to install this on top of normal 6" tall canopy, it would put the base of the pendant about 7" from the surface of the water, and the bulb would be about 10" from the water. At that distance, the PAR was between 1050 and 1200. As the sensor was moved outward from dead center, the PAR dropped to about 800. When it was brought to the edge of the 24" wide grid, it still measured about 540, the sensor still at that 10" distance explained above. I plan to do more tests with this particular reflector in the future when I get the opportunity to do this over water.
In the meantime, this test shows that while ballasts may not vary too much in wattage, the reflector choice can make a big difference in getting more bang for your buck. By only changing out the reflector, more light can be cast into the tank without additional expense of new bulbs and ballasts.