[sphelps]

Originally Posted by StirCrazy

the rating for 50,000 hours is right from the cree data sheet, as is the drop off rating for MH's the reason for the drop off in MH is due to the gas and rare metals inside being subjected to the heat inside the bulb. I was looking at the specks for the MH we use int he arena which last longer than the bulbs we use on the tank and they have a 60% dropp off after 20,000 hours and believe me I can tell looking at them as there are a bunch we need to change haha. the rating for the cree is something like 15% after 50,000 hours and because there is no gas or rare earth metals that are being heated and vaporized over and over there is also no color change. also running the new crees at 700mA instead of 1000, or even the rated 1500mA extends the life even longer.

as for running them 11 years I doubt it but I do know street light using high power LEDs have been around for about that so I suspect that the manufactures know what the actual drop off is as it only takes 5 years at 24/7 to get to 50000 hours.

like you I have run the full gambit of lighting, spent over 10K doing it on my 90 gal. wish I didn't but 10 years ago there was no info on lighting.

for the record I am a MH guy, I think T5s are way over rated but good for supplementing color, But I have been playing with Leds for about 5 years maybe more now but for the purpose of moonlighting and supplemental color as the powerful ones were just to expensive until recently.

now for a 30 gal tank (which I am putting together now although it will be a very slow build, as I have to insulate, drywall and heat my shop first) LEDs make way more sense.

this tank will be a SPS high light requirement tank.

the metal halide way I am looking at two fixtures at 250 watt each. I could get away with one, but from experience with my 90 gal and my PAR meter even using a good reflector looses a lot of light at the edges and I find the PAR drop off is significant enough outside of the 20 inch square. to even this out you have to raise the light farther which also drops the overall intensity. so in order to get the levels I want I am looking at two fixtures which will give me about 400 PAR on the tank bottom.

Also I will require a 12" box on top of the tank to enclose the fixture and prevent light spillage. kinda looks funny on a smaller tank

I also like a color in between 10K and 14K so MH bulbs alone don't cut it..

so a decent MH setup from J&L is 312 each x 2 is 622.00
to add 2 DIY T5 bulbs, standoffs, ballast and reflector is 170.00 granted most will be satisfied with 1 MH so for this example we will use 1. so 311.00 plus 170 = 481.00 plus what ever it costs to make you canopy.

if you want to go with a sleek fixture and have a open top like the LED will give me then you are looking at 583 for a 24" fixture with one 250 watt mh and two 24" t5s

for me to do LED for my tank I can get a 48 Ultra Premium LED DIY Kit with Dimmable Drivers for 460 plus 80 for the heat sink, so 540.00 all together. granted I have to build it. and we can add a little more to make it look sweet (like building a hood)

Now this set up with 40 degree optics will also give me PAR levels of 400 on the bottom of my tank.

so the initial purchase on the first MH setup is 60 bucks cheaper and the second MH is more expensive.

power consumption on the MH setup is going to be about 420 watts for a magnetic M80 ballast which I like better because of the higher outputs or about 350 watts for a fancy electronic ballast model plus the T5s so say about 70 watts so 490 or 420.

for the LED set up the power consumption with be about 146.88 watts so a little over 1/3rd of the electronic ballast option.

now the subjective parts. my preferred combo is AB 10K 250 watt SE with uri super actinic VHO the 13K of the ab's plus the URI VHO give a color that is simply unbeatable and the power to match, but the AB bulbs are 180 each. so now my MH set up is going to increase by 100 for a 1MH set up to 200 for a 2 bulb set up but if you like the look of other bulbs that are cheaper then thats a mute point. and I will use 80 buck bulbs as an average for this comparison.

so 11 years changing bulbs once a year for the MH setup is going to be
1430.00 assuming all bulbs last 1 year even the T5s
so now total costs for hardware is

MH 1911.00
LED 540.00

in my case the LEDs save me money before I turn them on, which for a small tank make it more desirable in a small single tank it will take 1 bulb change to make the LEDs cheaper.

lets talk about pros and cons on a small volume tank (say under 50 gal)

PROs

MH
proven track record and the power to grow anything well.
simple to buy and install
wide selections of bulbs

LEDs
proven track record up to 3 years in Canada and US is common, longer in Europe and Asia.
no radiant heat
any color combination you want changeable at whim.
lighting effects from gradual dimming to rock shows able to be made by adding a 70 buck PC controller like and adrunio setup.
directed narrow spread light so light is only where you want it.

CONs

MH
have to change bulb to change color
lots of radiant heat into water
large enclosure/hood required to contain light

LEDs
expensive for a ready made solution, cheaper if you have the skill to build yourself
shorter track record than MH, but still longer than T5's

one thing I haven't mentioned is actual electricity costs. BC has one of the lowest power costs in north America so on the example tank the difference might be only 8 bucks a month in power consumption but imagine what it might be in California?

another thing to note is actual power requirements to the tank area.. especially on a larger tank. how many circuits do you need for your MH lighting. even on my 30 gal in the example with the two 250 watt MH I will need two 15 amp circuits to run it. if I go with the LED I can run the whole tank on 1 circuit.

another thing that is a huge huge concern on a small tank that I haven't gotten into is heat. one 250 watt MH on a 30 gal tank is going to make a lot of heat and in most cases will require a chiller. so the cost of this plus the power to run it should be taken into account also.

Finlay I am not pushing LEDs only stating the opinions I have formulated over 5 or more years of tinkering with them, and especially from my research in the last year and a bit on the high power LEDs like the Cree.
they just make sense.. to many pros and to many savings.. it just to bad that instead of a 100% mark up that they companies who are making decent fixtures are doing anywhere from a 500 to a 1000% mark up over the cost to make them.

Steve

Steve, your 30 gallon example is worse than my 9x3 foot tank example . You're dreaming if you think 48 LEDs will compare to 500W of halide plus T5s. And who runs that much light on a 30 gallon? Also 40 degree optics shouldn't be used on a tank unless it's exceptionally tall, all you'll do is create hot spots because a 40 degree optic will actually concentrate most of it's light at around the 20 degree range or lower. You will not get the same par overall, you will get hot spots which may make you believe you do but you won't. But anyway like I mentioned very easy to make up bias examples to prove a point and anything other than that related to a 100 gallon tank size isn't that relative in this thread and the OP.

Couple other things I'll point out:
50,000 hours based on manufacture data sheet means nothing and I believe it's 30% drop, not 15%. Metal halide data sheets state the same deal, 70% remaining after 20,000 hours which is about 5 years (70% is that standard used for bulb life and is based on lumen output). We obviously sometimes experience more par drop due to color shift with certain types of bulbs but be aware that you can keep PAR constant with certain bulb types and using an HQI ballast. Efficiency and color is sacrificed but this may not be a concern as the power used will not be significantly more and if supplemental lighting is also used. Most don't look into this because they figure a couple bulbs aren't that expensive to replace on a yearly bases.

As for street lights some cities have introduced some but reports have shown they do not live up to suppliers claims due to moisture and different climate conditions so LEDs for reef tanks could suffer similar effects due to the moist environment. I did a feasibility study on LED streetlights using aluminum poles in university. The idea was to introduce aluminum poles instead of steel for safety and lower maintenance, we included LED lights to promote better payback periods however in the end the LED lights proved to be more problematic than we originally expected.

As for electrical circuit requirements, 500W of halide is just over 4amps so it can easily run on a single circuit in addition to other equipment. I just installed a bathroom vanity light in my house which uses 5 100W halogens, I didn't have to run a new circuit to power it. You do however typically want two circuits for any tank to have the ability to run life support equipment on a separate circuit.

Since LED fixtures typically only use blue and white LEDs the amount of color changing ability is actually very limited. You could add other colors but it's not very common practice and it's not always that easy to blend them in to avoid color spots. T5s can also be dimmed and with a range of bulb colors and with the ability to change them so easily you will find better color options available in T5s.

It's also pretty hard to tell what a company is using for mark up, 500-1000% percent is highly unlikely. Why don't you start up a business, lease a plant and all the equipment you need, hire workers including at least one electrical engineer, cover all the R&D for development, hire customer support, sales, marketing and possibly even patent costs to protect your own designs or to use another companies. Oh and then make money too. It's not the same as building a fixture in your basement that looks like an electrical hazard and saying "wow that's way cheaper, those companies are just ripping people off".