Thursday, December 10, 2009

new aquarium lights

Some of you may know that I keep a salt water reef aquarium (210 gallon). Well, one of the challenges with such aquariums is lighting -- most corals need a large amount of high quality light to grow.

Most systems use metal halide lighting, which is extremely bright, and extremely hot. On my aquarium I've used three 250 watt MH lights, supplemented by a pair of 150 watt MH lights. (The 150s have been out for a while due to a bad ballast.) Yes, that's over a kilowatt in lighting. And MH lights have historically been considered some of the most efficient lighting -- i.e. most lumens or PAR per watt.

One alternative that has been up and coming has been LED based lighting. High power LED systems offer a lot of potential capabilities (although due to a patent problem that has put at least one company out of business and probably set the industry back at least five years, software based control of LEDs is only available on extremely expensive lighting systems -- systems costing thousands of dollars.

And until recently, inexpensive LED lighting simply did not exist.

I recently had cause to investigate this, as the bulbs in two of my 250s have died recently -- and I'm particularly unhappy with 250 watt MH lighting for several reasons: heat, problems with bulb fit (whoever designed the mechanical interface used for 250 and 400 watt double-ended MH lighting needs to quit mechanical engineering -- I've had numerous problems getting the bulbs to stay put in their "friction" based holding interface, and broken a couple of bulbs trying to increase tension so that they wouldn't fall out of the fixture), and power consumption (power in California is very expensive.)

Anyway, I'm happy to report that I found a good alternative. LED offers a 120 watt LED fixture intended for this application for just over $300. (They have an eBay store where the fixture can be purchased for under that, but with shipping and our ridiculous 9.25% CA sales tax, you'll still be over $300.) Compared to other options, this price is ridiculously low.

I put it on my aquarium yesterday, and comparing side by side with the remaining 250 watt MH fixture, I think the fixture "appears" to be about equivalent to a 250 watt MH. I've not measured it precisely, but the light appears about as bright as the 250 MH (the wife says brighter, but I'm not sure), although the spectrum is a bit bluer. If I had to guess I'd guess the spectrum to be somewhere around 18000K.

Anyway, I thought I'd post this here, since I think I'm one of the very early adopters of this. I'm going to monitor the health of my corals, and if it goes the way I hope it will, I'll be purchasing two more of these units to get full coverage over the entire aquarium. I might even purchase one for my 56 gallon tank. (I might supplement with another 100 - 200 watts of compact fluorescent at ~6500K though. That's still only about half as much power as my system previously consumed.)

I'll return to this post in the coming months to report my results as I get more experience with these lights.

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