Bulb Comparisons

So I borrowed Kirk's Iwasaki bulb and it's really not so bad.  It is most definately yellow and washes out the greens and blues, but it's very bright.  Here are some pictures of my tank taken all within the same hour after the bulb had been on for about 10 min. 

For background:

Left:  250 watt MH (10k Ushio ~3 months old)
Middle:  400 watt MH (20K Coralvue ~5 months old)
Right:  250 watt MH (Test Bulb)
VHO:  Two 160 watt URI actinics (~6 months old)

Ushio 10k (about 1 yr old) on right:

 

Coralvue 10k (about 3 months old) on right

 

Iwasaki 6.5k (~6 months old) on right:

 

Sunburst 12k (~6 months old) on right:

 

No bulb on right:

 

 

Lighting is such a personal thing and although these pictures do show differences, they don't really show the whole picture.  The color of the old ushio is still ok (it's yellowed a bit) but the intensity has dropped off.  The Coralvue bulb is kind of an enigma.  It started out gangbusters... brighter then the Ushio and just as "white", but you can see it's shifted a lot to the red.  The Iwasaki is VERY bright (I like), but it really washes out the color... bummer.  The Sunburst is listed as a 12k bulb, but to me it resembles a 20k and as you can see, it's intensity sucks (although there might be plenty of PAR light there that we don't "visualize").

Just out of curiosity, what are those white blocks in the back corners of your tank?

I remember that post back in Nov, I was the one that asked the q about overflow noise.    NOW youre pics make sense to me (it only took 7 months). thanks

Brad

I really like your comparisons Jon, it does a lot to actually see what each bulb looks like sitting next to each other.

I'm not sure if you've seen this site but it's defiantly worth a look:

http://www.cnidarianreef.com/lamps.cfm

A friend of mine had a 20K XM bulb that was incredibly blue (too blue in my opinion) it stayed that way for about 10 months and the just dropped off fast.  He replaced it with a 10K MX bulb and after 2 months it still looks great.  I am interested in how they do over a longer period of time as that's the bulb I plan on replacing my current bulbs with.

I have two 6 ft VHO actinics and the center metal halide is a 400 watt 20k.  My other two bulbs are Ushio 10k right now.  If you want those particular green stars to glow you will need actinic light (420 nm), not "blue" light.  There's a good chance that your PCs are "blue" and not actinic.  But actinic PC bulbs can be had from places like www.hellolights.com or go ahead and convert to VHOs.

I disagree with Jon.  You don't need actinic light, you need blue light.  Blue light being around 420nm so I guess in that aspect I do agree with Jon.

You disagreed and agreed in the same statement .

Violet:  380 - 430 nm
Indigo: 430 - 450 nm
Blue:   450 - 500 nm

Those blue PC bulbs and some T5s do not peak at 420 nm.  Probably closer to 475 nm (which is the wavelength of "blue").  "Actinic" lights peak closer to 420 nm.  They are called "actinic" because the definition of actinic is electromagnetic radiation that produces a photochemical reaction.  The wavelength is dependent on the photochemical reaction... it just so happens that at 420 nm the pigments in the corals "react" and glow.

LEDs emit an almost monochromatic light.  I have a blue on (470 nm) and a violet one (410 nm).  The difference between the two at night are dramatic to say the least.

Jon,

Disagree again.  I think most actinic light out there is Red!  However, in the hobby we get use to thinking that actinic light is blue.  We use those terms synonymously but as you said, that isn't the definition of actinic.  It is another Adam pet peeve to hear people saying it.  I cringe.

Anyway, I do think you could have a wonderfull blue light at 420nm (okay for you I'll call it violet) that would look great.  For me, my pc actinics never looked as good as my pc blues.  I think my pc blues are much darker (closer to 420) and my pc actinics had much more white mixed in with the blue (which was closer to 470). 

I guess what we do agree on, is that we both think a light of 420 is best, but I still like a spread, and not a monochromatic light.  That is why I think LED's will have a difficult time taking over the aquarium market.

Adam

I love, absolutely love symantics.  I may not have learned much in school, but that is one area I studied.

As for LEDs.  I agree with Jake (I think Jake still has this impression) that LEDs are bright enough.  Those super bright leds, imagine like a panel of 5,000 of them above your tank.  But they are costly, and they don't have that halide shimmer.  
But manufacturing a big panel of them and getting a wide spectrum would be a pain. 

Adam

(oh yah, I don't think combining your spectrum would be fun at all, I just like buying my lights and setting them up on my tank) 

As for LEDs.  I agree with Jake (I think Jake still has this impression) that LEDs are bright enough.

Maybe I'm missing something but I don't see it.  Those really bright LEDs are in the neighborhood of 12000 mcd (blue) to 24000 mcd (red) at a viewing half angle of 10 degrees.  If you use an average candela rating of 15000 mcd (you'll want more blue then red) it works out to about 1.4 lumen per bulb.  Let's say you could fit 11,400 LEDs over a typical 90 gallon tank.  That's only about 17,000 lumen.  One 250 watt MH bulb is more then that.  But I must be wrong, 'cause everyone say's they're the light of the future

(I've got a skunk clownfish swimming under blue actinics )

Edited by jfinch