Lighting question - Halide 10K / 14K / 20K ? And how about those Actinics?

[Origami]

My 150W 10,000K DE HQI halides have been running about 8 hours per day for going on 4 months now. I'll probably be faced with a routine change of the bulbs in 2-3 months or so given what I've read. This will be the first time I've changed the bulbs so "routine" is not a description of my routine, but just from what I've seen recommended.

 

Anyway, I've seen several color temps talked about and advertised: 6700K, 10000K, 14000K and 20000K. I understand the lower the temp, the yellower the light and the higher, the bluer. What I'd like some input on is 1) Is the selection going to make much of a difference on my coral health or growth rates, or is this pretty much a selection based on what "look" I want to achieve. 2) What really is the difference between the "look" that can be achieved? I really don't want to spend a lot on a different colored bulb and find out that I liked the old look better, you know? Is there anyplace around where I can compare one "look" to another? 3) If I do change color temps, can I just change the bulbs out to make the switch or should I ease the old bulbs out and ease the new ones in by backing off then adding to the photoperiod of the halides? (Should I do this anyway because of the new lighting's output?)

 

Regarding Actinics, my fixture has two 96W power compacts of the Actinic 03 variety which I've found puts out a spectrum around 420 nm. I've seen advertised both 420, 460 and hybrid 420/460nm actinics. What's the story here?

 

I understand that lighting can be a touchy subject with a lot of different thoughts and opinions, so I'm not looking for a definitive answer, just opinions, guidance and resources.

 

Thanks.

[Rascal]

I know what you mean about not wanting to buy new bulbs only to find out you don't like them, but it is really hard to look at pictures and get a good idea how the bulbs would really look on your tank. So much depends on the camera, white balance, photographer, and photo-editing. Best thing you can do is probably go look at some other tanks and see for yourself.

As for actinics, I have experience with PC actnics, T5 true actinics, T5 blue + actinics, and VHO actinics. First thing I would say is ditch the PCs. T5s will give you much more light for 1/2 the wattage. As for color spectrum, I think the 420 mimics what is actually found in nature (so is supposed to be better for growth) but it can be kind of purple, IMO the 460 just looks better / bluer. Since you have MHs I wouldn't worry about trying to use your actinics to boost growth. I switched to the blue+ T5s last summer after a year with the T5 true actinics and was much happier with the look of the bluer bulb. I also run VHO actinics on my system. I have them stay on by themselves for the last hour of the tank's light cycle and it is probably my favorite time to view the tank. Everything you may have heard or read about how VHO actinics just make the colors "pop" better is absolutely true but you really have to see it to believe it. Overall I am very pleased with the combination of both T5 and VHO for actinic supplementation and I highly recommend it if you've got room for both.

 

Now on to Halides. I run 250W DE bulbs on my system. I started with Ushio 10Ks, but after about 10 months I started to think I wanted a little bit more blue, but I didn't want to lose the pinks & reds in my system either. Some reds (RBTA, red shrooms, rose millepora) really seem to look great under blue light while others (birdsnests, pocillopora) just disappear. I was also concerned with PAR. I run 3 x 250W over a 2' x 5' x 2' tank, so I could probably get away with more of a PAR loss than you (with 150Ws) but I didn't want to if I didn't have to. So I was looking for a little bit more blue without losing the reds and without a significant drop in PAR. After a ton of research, I settled on the ushio 14Ks, but since I wasn't entirely sure I'd like them I only put them in the two outside bulbs and replaced the middle one with a new ushio 10K. First observation was that a large part of the reason I wanted a bluer look was my bulbs needed replacing. Second observation was I absolutely loved the ushio 14K. They gave me just the look I wanted with a very slight drop in PAR. But . . . after about 3-4 months I started to suspect the two 14K bulbs were looking yellow. Eventually I could no longer deny it. With all three bulbs on at the same time, the two sides of the tank looked yellower than the middle. I started searching around and it turns out that some others have had a similar experiment, and not just with the ushios, but also with other 14K bulbs that had a significant color spike in the red end of the spectrum as well as the blue. I am sure others have been perfectly happy, but it was enough to convince me the 3-4 month lifespan wasn't just a fluke or my eyes paying tricks on my, so now I am back to 10K ushios for all three MH bulbs. Older, wiser, and poorer for the experience.

 

If you have never looked at Sanjay Joshi's test results, have fun: http://www.reeflightinginfo.arvixe.com/ I think there are more bulbs he has reviewed since that aren't on that site, though. You might want to check the RC boards for more info. HTH.