Par 38 LED spotlights

here's a pic of my tank with my par38 bulb. It's an 80 degree spread placed @ 10 inches off the surface of the water. I'm aiming to place high light requirement corals in the middle, and yumas/shrooms on the much dimmer sides.

<a href="http://www.flickr.com/photos/davenip/4318342814/" title="IMG_1445 by _dpn_, on Flickr"><img src="http://farm5.static.flickr.com/4068/4318342814_8e2cb64a5b_b.jpg" width="1024" height="681" alt="IMG_1445" /></a>
 
I apologize if this is somewhat of a hijack, but I think it'll be an interesting case study for evil... I have a 90g tech tank (4ft) and am currently running an outer orbit 2x250w hqi metal halide and 4x54w t5ho's. I need to order replacement bulbs (2 metal halides and 4 t5's) which will cost me about $330 for quality bulbs that I can count on for a year. Instead of ordering new bulbs, I am considering lighting the entire tank with evil's par38s.

It's a deep tank - about 22" when you factor sand, but I don't keep anything very deep that needs a ton of light... The tank is 4ft long and about 17" wide. How many par38s would I need to light it sufficiently? How would the amount of light available to corals compare to my current setup?

Evil uses 5 par38s on his 40 breeder. My tank has the about the same footprint, but it's just 9 inches deeper. So if I don't keep anything that needs a ton of light on the bottom of the tank, 5 par38s should do the trick - right?

Think about the cost difference. Even without selling the outer orbit, if I have to replace bulbs in the next two years - that's $660.

I could buy 5 par38s for $500 and probably get the track lighting done for about $100. That doesn't even begin to include energy costs.

What do you guys (and evil) think? I know par38s were designed with nano tanks in mind. Am I crazy for trying to light a 90g with them?
 
I have been tossing around lighting my 90 gallon tank with Par38s too. I think the ability to focus light in a certain area of the tank is a big plus. I think the beams of light in the tank would look very natural like rays of sun light penetrating the water. I was wondering what optics would be best to light a bigger tank and if you should use a mixture of bulb colors. If anyone has used these on a larger tank please let us know. I would love to see pictures and hear feedback from a person with a tank 75 gallons and up.
 
je_unc said:
I apologize if this is somewhat of a hijack, but I think it'll be an interesting case study for evil... I have a 90g tech tank (4ft) and am currently running an outer orbit 2x250w hqi metal halide and 4x54w t5ho's. I need to order replacement bulbs (2 metal halides and 4 t5's) which will cost me about $330 for quality bulbs that I can count on for a year. Instead of ordering new bulbs, I am considering lighting the entire tank with evil's par38s.

It's a deep tank - about 22" when you factor sand, but I don't keep anything very deep that needs a ton of light... The tank is 4ft long and about 17" wide. How many par38s would I need to light it sufficiently? How would the amount of light available to corals compare to my current setup?

Evil uses 5 par38s on his 40 breeder. My tank has the about the same footprint, but it's just 9 inches deeper. So if I don't keep anything that needs a ton of light on the bottom of the tank, 5 par38s should do the trick - right?

Think about the cost difference. Even without selling the outer orbit, if I have to replace bulbs in the next two years - that's $660.

I could buy 5 par38s for $500 and probably get the track lighting done for about $100. That doesn't even begin to include energy costs.

What do you guys (and evil) think? I know par38s were designed with nano tanks in mind. Am I crazy for trying to light a 90g with them?
Click to expand...

So I blew it on the dimensions of a 40 breeder - it's a 3ft tank - mine is a 4ft tank. So my tank is 9 inches deeper and a foot longer...
 
Evil,

Do you have plans for anything with lousy colour, but high PAR? I run a turf scrubber (8" x 8") with a couple 24 watt compact flos. Lots PAR when new, but the PAR drops quickly @ 3 months. If I could get a decent LED solution together, I'd switch in a heartbeat since I don't like the number of bulbs I have to throw out.
 
evilc66 said:
It can certainly be done. To start off, I'd use at least 6 or 7 with 40 degree optics. You should be able to hit 250W MH PAR levels throughout the height of the tank, but with a more narrow focus. 6 or 7 lamps should keep coverage reasonable, but PAR will still rise and fall as you transistion from one lamp to the next. What is great here is that if you need more light in a certain area, it's not hard to add one, especially if you use track lighting to mount everything. I would think that you would have to add one or two more over time as you figure out where you need more light.
Click to expand...

When you say "250W MH PAR levels" - do you mean as if I had a single 250W over the tank or the equivalent of 250W MH PAR equally distributed?
 
I'm going to go for it. 6 of evil's lamps over a 90g 4ft tank. Now the question is - what color temps and how many of each. Evil, I noticed that you mixed 12k and 20k bulbs over your 40b with an all blue in the center. Would you do it the same way if you had it to do over again? Do you think the all blue bulb adds anything? I know you said 40 degree optics, but would I want an all blue or two with a wider spread? Those are a lot of questions, but I really appreciate your insight.
 
he mentioned throughout the height of the tank which leads me to believe that you will get that PAR reading across the entire top of the tank with a slight PAR dropoff between bulbs

now i have not used these bulbs but i have seen a bunch of people on another nano reef site that love them and i am planning on getting these bulbs in the future for future tanks because i love everything im reading about the new LED lighting that is hitting the market
 
I was wondering if there is a differnce in PAR numbers between 12K and 20K like in metal halides, or if LEDs didn't vary based on kelvin temp?
 
PAR for 12k is the same as 20k the Cree leds in White and Blue put out the same PAR evilc66 told me that even if you went with an all blue PAR 38 bulb you would still get PAR the same as the 12k the spectrum is the only difference all the LEDs are 3 watt

I'm setting up a 200g DD tank and most lilkely will be using these spot lights to light it, of course it will be trial and error as everything is, but these lights look like the best option

he has the lights 33 inches of the sand on his 40br so on the 200g DD that puts the lights about 6 inches off the water, IMO that would be enough for PAR at the bottom to keep softies and lps and at about 5-10 inches off the bottom i should be able to keep sps perfectly fine
 
evilc66 said:
Correct. It's not as even of PAR coverage as with a DIY LED setup, but that could be a good thing. It can give you a little more variety on where to place corals that you normally wouldn't be able to do with other light options. One thing to keep in mind is that while the coverage on the sand will be pretty good, the cone shape of the light output will make the upper portions of the tank not evenly illuminated. Again, you can take advantage of that fact with lamp, rock and coral placement.
Click to expand...

i think that effect would make for a really nice reef tank since you wont have the levels of corals ei. bottom being all softies then working up to LPS then SPS. With this kind of lighting you could have everything from softies to SPS throughout most of a tank which would make for a very nice tank
 
i have seen something like that done with a MH before it looked pretty neat. he had a rock structure near the MH and it tapered off to just open sand where there was a macro area where there was less light.
 
evilc66 said:
The 40 degree optics give you the most PAR at the greatest depth. If you look a the third chart, you can see that you get ~15-130 PAR at 30", depending on how far off center you are from the lamp.

For a tank of your size, I would say you would need at least 6 lamps mounted about 30-34" off the sand to get a good mix of light levels for a good mixed reef.
Click to expand...

So from reading so far, the par doesn't really variate from 12k to 20k. so for SPS, what color combination should I go for and should I still go for 40 optics on all 6? Also, should a small fan be blown against the heatsink?
 
uhuru said:
I got one mounted on the Lowes track light too. The 20K is very blue. Still waiting for 2 more! The track light is kinda cheapy but you get what you pay for. I don't mind it too much, but my lights are mounted pretty far from my tank so it doesn't really take away from the rimless elos. Directly over a nice rimless tank then yeah I can see it looking kinda bulky.

DSC02780.jpg
Click to expand...

Do you have the model number for that track and how much it cost? Is it a pluggable one or one that has to be wired to the house lights?
 
should do a rainbow LED bulb :P jk might be interesting though.

Waiting for Nanotuners to get more of the 20k in stock and need to find the fixture before I can buy anything :P

Would a thin acrylic sheet covering the opening of the tank affect the light?
 
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