mr.wilson
.Registered Member
The best advice is honest advice, no matter how how much we don't like it
Changing optics seems to be the best solution for the Orphek LED. I tried angling it from 30-40˚ and it looks much better. The hot spot on the bottom is diminished/blended and max PAR just below the surface is lowered from 900 - a more usable 600, and the PAR on the substrate is knocked down to 150-200 where we want it.
One possibility is we position the lights parallel to the tank with one light on either side of the duct work, then angle them in to spread the light. This is my usual method as it directs light away from the viewing panels where algae can grow, and on to fish and corals for fewer shadows and better photosynthesis. We tried this briefly, but there is still a hit spot and it gets in the way of tank access.
Taking a second look at the light a day later gives new perspective. I measured the suspension distance and the light was only 6.5" above the water surface, not 12" as I had thought. I was able to raise it another 2" which helped marginally. The problem remains that the emitters are too bright for the optics (lenses), resulting in a spot light effect. The light is a victim of its own success. The next step is to try 120˚ optics to dim the centre of the "beam" and brighten the outer margins. Right now the sand looks vivid white/blue under the lights footprint, then yellowish in the outer margins.
I tried the light on a 30L x 30W x 26H tank last night and it fit much better. I was able to mount the light as high as necessary, but it still had the same spotlight issue, but to a lesser extent. Angling the light is an option, but I believe wider or frosted optics is a better solution.
I have been talking to the manufacturer about a special order version without fans, on board ballasts and using a third party controller instead of the built-in timers. This should trim some cost, reduce noise, and save space. We can informally call it the Mr. Wilson Signature Series (unless it burns the diodes out)
Another suggestion I will make is to design the light to cover a modular 2' x 2' footprint so it can be adapted and scaled for typical tanks of 2'L x 2'W, 4'L x 2'W, 6'L x 2'W and beyond. The problem there is when you get custom tanks that are 30"-36" wide, and deeper than 24" as in Peter's case. You need 1.5 lights to fill the space so you either over illuminate or under illuminate to fill the gap. We took a hard look at the light on the 100 gallon tank last night and it looks like it's a keeper, once we dial in the optics. It will be replacing a 1 x 250 watt HQI + 4 x 24 watt T5 Giesemann fixture. That's 120 watts vs. 346 for a 226 watt reduction. I tested the 1 - 2 year old MHL bulb for PAR and it was a frighteningly low 30 (not 300) 30" below the light with no water in the tank. This is the one factor that is tipping me in favour of LED, no bulb replacement, colour shift, uniform colour, and no loss of intensity over time. A lot of the LED proponents brag about how much energy it saves, but we only pay $0.12/KWH here in Canada, so the savings isn't as dramatic as it is in California for example. In this application, you would save $8.25 per month in energy costs. A typical T5 or ML fixture would cost half as much as the Orphek so it would normally take five years to pay off, but in this case the Giesemann fixture is actually more expensive. Once you factor in $158.00 per year for new bulbs, it closes the gap significantly. In other words, you save $158.00 per year in bulb costs if you switch from MHL to LED, but you only save $99.00 in energy cost. Don't get me wrong, I'm all in for saving the planet, I'm just pointing out that the greater share of operating cost comes from bulb replacement, not energy.
I will post some pics of the comparison in a few minutes.
