Par 38 LED spotlights

[nattarbox]

Both of my lights have optics, the 40 seems to exhibit the peripheral banding more than the 60. I haven't been able to try them together, as I only have one temporary fixture available for testing. As you said, cameras have a hard time dealing with lights this bright, but looking at your second photo I can sort of make out some of what I was talking about.

The yellow is most visible on rock and substrate. I'll see if I can get a quick photo in my tank.

 

[nattarbox]

The weird bit is if you just aim the light at the floor, it is a solid blue beam exactly like you'd expect. All the colors seem well mixed into a nice 20k blue with no sign of yellow. I might just be overly sensitive to how it appears within the tank.

 

[nattarbox]

Here are some snaps. These were taken with the same white balance on the camera, but I tweaked the curves and levels to be as close to what it looks like in person as I could get it. Even still, the effect is more pronounced than it appears in these photos.

First is my 150 watt metal halide fixture with a 14k bulb:

Here is the PAR38 20k with 40 degree optics:

And a close up with indicators of what I'm looking at:

Two thoughts:

1. This might all just be overreaction by a color sensitive nerd who should have known better than two switch both technology (MH to LED) and spectrum (14k to 20k) in one go.

2. The color banding I see seems to be specifically where the shadow of a coral or rock is blocking the LED light. If I move the spot around, those yellow and blue areas I highlighted move as a shadow would, stretching out or shrinking based on where the source has moved.

 

[JTL]

That is weird. I just don't see that happening in the tank. Technically, water can separate white into it's composite colors, think a rainbow, but the water is too deep for that. My optics are all 40 degree. Does the height of the light make a difference? Mine are about 30" from the top of the sand.

 

[nattarbox]

Moving the fixture up and down would change the position and size of the shadows, but it didn't seem to make the yellow/blue edging go away.

Those photos were snapped at 6" above the water surface, so 24" give or take from the substrate. The overall lighting effect seemed more 'natural' at around 30", but I still got the color separation issues.

Hopefully I will be able to grab some cheap fixtures tomorrow so I can at least see what the two look like together over the tank and how the corals react.

At some point I'll have to decide if I want to keeps these, and maybe invest in a third 12k bulb to tone back the blue a bit, or stick with MH. One reason I moved over to LED is that the screw bolts for the glass plate on my MH lamp (Current Sunpod) have corroded and the moonlights have stopped working.

 

[JTL]

Here is a theory. The LED's are projecting the blue, but if it gets blocked, then the white spectrum is bouncing around and what you are seeing is the natural color of the rock and substrate contrasted against the blue tones and it stands out. I really think it is a function of just a single lamp and lots of rock to cause shadows. I am not at home so I can't really take a careful look at my tank. These spots are so concentrated that we need to do one of three things or a combination of all of them: (1) more spots to blend them without reducing par (2) raise the height to get more coverage and less concentration and of course less par or (3) use optics to spread the light. For me it took a while to get used to the subdued blue/purple color because I was used to much brighter T5's. Now I like the look and it doesn't feel like someone turned on a tanning bed light in my living room. I also think it is a plus to be able to aim the beam to highlight specific areas. I think when you get both of them going you will notice a difference. I think you will need 3 to get good coverage and keep the par up. Were it me I would order a 12K and put it in between the two and swap the 60 optics from your 20k to get some spread. Or if you want to keep the 20k look get another one with 40 optics and put the 60 optic on in the middle. It is a major change but look how the colors pop compared to your MH. I am learning myself so take what I say with a grain of salt.

 

[nattarbox]

Yep, I agree with most of that. I think mostly I just am somewhat in shock at the aesthetic difference between a light I've been using for nearly three years and these new guys.

I'm going to get both in place and see how it looks, give myself and the corals a week to pass judgement. You could well be right about the different blue/white lights being blocked in some cases, and having both fixtures running simultaneously might offset that, as could the addition of a third.

I just want to make sure that I feel good about committing to this technology before investing in a third light.

 

[JTL]

There is no question that the difference is dramatic. Let us know what you think using two lamps.
John

 

[Dun Properly]

Natter,
Not that this helps you at all, but the pictures of the LED lighting look 10X better in my opinion. I would try to get used to the shock of changing bulb type a spectrum if I where you.

Oh, and I don't use these LED's (or any LED's actually) so I feel impartial.

 

[nattarbox]

Thanks for that.

I got both lights rigged up this morning and it was an improvement. I think the addition of a third bulb with wider optics, and possibly the 12k color, might make a big difference. Right now I have a good spot on the Montipora cap in the middle, and a decent wash of light across the rest of the corals.

One factor I didn't consider is that the Sunpod fixture I was using before did an excellent job of hiding the skimmer, fan and HOB filter I use for an algae tumbler. With these minimal spots, all that ugly equipment is wide out in the open. I had a crazy shower idea of gutting the Sunpod fixture, removing the bottom panel and mounting light sockets within it. The other options would be a standard aquarium canopy.

I'm going to poke around with the Sunpod tonight and see how feasible it would be. It already has cooling fans built in, so that could be a good benefit.

 

[beeker]

i love the difference between my MH/T5 setup and my LED tank, and not to be biased but IMO the LED tank looks far more natural and better looking than my MH/T5 tank does although i may not be getting 100% coverage over the whole tank but it does look better because of this fact,

i've had friends that aren't even into the hobby say the same thing as well about my 200g when they see it

Here are PAR plots of a single 12k PAR38 with 40 optics, this was at the very bottom of my tank, the tile is 13 inches long and the 0 point is 6.5 inches in from the outside

As far as noticing the yellow/blue Led's....i don't maybe it's more pronounced because you have sand to reflect the light back to your eye's and since my tank is BB the ligh goes straight through into my sump without being reflected, if you look at the bottom glass from above you can see the LED's but when looking at the tank from the sides or the front you can't tell the difference between the whites or the blues

I get the led RAVE effect around some of the rockwork but honestly i like it like that, it's a different kind of shimmer compared to MH but IMO it looks just as great

here are the pics everyone wanted, lol

Dead center of the PAR38 12k 33 inches away from the bulb

Dead center again, highest PAR hit was 198 but wasn't able to get a pic of it

1 inch from center PAR of 170

2 inches from center PAR of 165

3 inches from center PAR os 133

4 inches from center PAR of 103

5 inches from center PAR of 74

 

[beeker]

6 inches from center PAR of 48

7 inches from center PAR of 33

Excuse my chicken scratch handwritting, lol

 

[JTL]

If the lights overlap the Pars should be additive, correct. By the way Beeker, you have done an excellent job providing important information about these lamps.
John

 

[beeker]

not a problem, i'm a very visual person and most of the times reading things is a lot harder for me to understand than pictures are

yeah when they overlap there is an increase in PAR, with my bulbs about 6 inches apart in the middle where they meet PAR is around the 130 Range it's a good increase, and i've found it takes a PAR of 180+ to keep sps and 180 and lower for anything else, this includes leathers, Monti's, digita's, birdsnest, lps, hammer, frogspawn, chalice, lobo's, plate corals, gonipora and elegance

clams like a range from 150 PAR and up which means i will need to get another bulb to put in the front of my track setup in the middle of 2 bulbs where the clams are since the maxima isn't getting a full 150 but i raised it up on tiles to give it some more, going to see if that helps it in the next few weeks

 

[JTL]

I am surprised the par for your overlap isn't even higher. If I understand what you are saying it is that the 6" radius of the beam on the bottom of the tank is almost completely overlapping the adjacent lamps beam since the project a 12" diameter circle. The middle of the two beams is 3" which is a 133 par without the additive of an equal amount. I am not understanding this?

I am new to corals so I am trying to get a handle on the lighting requirements. I currently have just a few zoa frags and couple of small lps. I was going to go with mostly lps, but lately I have been thinking about more sps since there are more frag packs available. It is mandatory for the lps to have less than 180 par because based on your tests I will exceed that anywhere except the bottom of the tank. Maybe you could give me some hints on what to buy.
John

 

[dcook]

Beeker NO PICTURES

 

[beeker]

i exceeded photobuckets bandwith, so the pics got kicked, i upgraded to pro so they should be back up today, sorry about that, lol

 

[beeker]

if you go with LPS you will not be displeased at all, the 40 optics will keep the LPS fine, the thing is where the center of the bulb is PAR will always be higher so keeping LPS in the center of the bulb they will have to be acclimated for it to keep from bleaching them

I've noticed my LPS love the LEDs, the big elegance i got 2-3 weeks ago has been doing wonderful under them as well as all my other LPS

I'm still waiting on my Sps to color up and start growing, but dealing with a new tank and a not 100% stable system that might still take another month or two to get the results

the PAR is the center where the bulbs overlap does increase but honestly it is only by about 30-50 PAR, so 180-190 would probably be the most you could Expect, although any LPS, chalice, hammer, frogspawn, plate corals, gonipora, elegance and Zoa's should all do get at a PAR of 130-180 that is typically more than enough for LPS and softie's

Sps need a PAR of 200+ to get good color and growth, or atleast from looking at my BC29g MH/T5 setup, most of my sps in the BC29g tank were getting a PAR between 200 and 250, so really anymore than that is overkill but i do have some sps in the 400 PAR range in my 200g so i'm keeping an eye on them to see what the affect is, so far they look good, now just waiting for things to grow and color is all that is left for me

still only doing weekly WC's to the 200g and not dosing yet, though i might start in a month or so to get the tank to be more stable

 

[BennyFrank]

Thanks for posting the PAR numbers beaker, very helpful.

Question for you... When you say that your bulbs are ~31" off the sandbed, that is from the surface of the bulbs (where the light would be originating from), right?

What is the distance from your ceiling to the bottom surface of the bulbs (including; track, fixture, bulb)?

 

[beeker]

The PAR38's are 6 inches off the water, the tank is 27 inches tall, that puts the bulbs 33 inches away from the bottom of the tank (where i took the PAR readings), spread is 13 inches at this height

if you lower the lights spread is cut but PAR increase's

i have no clue how low my track lighting hangs from my cieling i'd have to measure it for you, i have the track with S hooks holding it and then chain is attached to the S hooks, from there the chain goes up to another S hook that is attached to anchors in my cieling

a rough estimate of distance from cieling to the bottom of the bulb would be 1 foot or a little more, i'll measure it tonight

it's a simple setup and i can add more sockets or remove sockets if nesscessary, i went this route for it's flexability