actinic question

[trble81]

I've got sort of a n00b question here:

 

Other than the wavelength, what's the difference between a 420nm actinic bulb and a 460nm actinic bulb? I guess a better question would be what's the advantage of using one over the other?

 

Thanks in advance!

[gastone]

I've got to respond before James pre-disagrees with me.

 

The application is different. First off I'm assuming that you are talking PCs here. I don't use too many PC lamps, but if we keep it to just wavelength it shouldn't matter. First off, you probably want a good balance of 420nm and 460nm(450nm for us T5 users) on your tank.

 

420nm is what us reefkeepers call true actinic. Very far to the left on the color spectrum This is quite purple in appearance. 460nm (again, 450nm for me) is much more blue in the spectrum.

 

In this graph the blue is what I currently use, the red is what I will be switching over to as soon as I get ahold of the appropriate ballast.

 

So my current halide lamp spikes at 420nm and has very little output in the 450nm range. A few years ago when I added actinics they were VHO superactinics (many view these are the "real deal" 420nm actinic lamps). The problem was they were supplementing what I already had, which is 420nm. I could hardly tell when they were on. I switched over to T5 ATI blue+ lamps (450nm spikes) and the results are dramatic. I now have a much more "complete" spectral output. The results are astonishing. Nice, crisp white. Everything looks good.

 

In the near future I'm switching over to radium halide lamps (the red graph). These on the other hand spike at 450nm and have very little 420nm output. So I'll be switching back over to true actinic (420), for the best complement. Truthfully I'll be adding both 420 and 450 by tacking on another 2-T5 lamps to the setup. But if I only could do it one way with the radiums it would be true actinics.

 

How'd we do?

 

G.

Edited February 3, 2008 by gastone

[trble81]

I should have said that I was talking about T5's, not PC. I was looking through a Dr. Foster and Smith flyer-thing and noticed that some of their T5 units had 420's and some had 460's. Just was wondering what difference, other than the wavelength, is there between the two.

 

So if I understand your post, you noticed a change visually? I assume more "pop" to the colors under just actinic light, along with the "crisp white" overall look that you mentioned?

 

 

Also, I plan on having 10,000k and 460nm T5 bulbs on the tank...just curious about the difference between the two, that's all...

 

 

Thanks for the response!

Edited February 3, 2008 by trble81

[gastone]

Pop, shmop. I'll let others tell you about that one.

 

If you are going with just T5 (sorry that I assumed PCs as those are the only bulbs I could recall that came in 460nm) then it is a whole different ballgame. Depending upon how many lights you have on your tank, what types of corals you have and are planning to have, what ballast you are using, and what color spectrum you are trying to achieve, should dictate which bulb combo to go with. Now things get really screwy.

 

Last one then I'm done. On my 30g tank (which is mostly for frag growout, but which will be converted to a zoanthid/LPS tank) I currently use this combo: 2x39W T5 (Aquablue and Blue+) and 190W VHO actinic. I am in the process of switching over to all T5 lamps (as of this Monday... hopefully) and my new combo will be (front to back) blue+, UVL SA, pro color, blue+. Not hot as far as par, but the zoas and LPS don't need outrageous par. The blue+ and SA will showcase the greens and blues in the tank, and the pro color will showcase the reds, oranges and yellows.

 

In this case I'll be utilizing bothe 420 (SA) and 450 (blue+) with more 450, 'cause I like them better.

 

Garrett.

 

 

 

 

Mike,

 

most hobby 10k lamps (most) spike at 420nm. The best complement for these is 450 (or 460 if that's your thing) lamps.

 

 

G.

[Big Country]

If you want to figure out a good setup for T5 bulbs look in the lighting section of Reef Central, there is a monster Q & A thread on T5 lighting. I just recently replaced my bulbs, because they needed it, and read through most of that thread until I found someone with the light fixture I have and the type of tank I have. Read the recommendation of bulbs and bought them from reefgeek.com. Just installed them a few days ago and couldn't be happier, a little bluer than my old bulb combo but the 'pop' in the corals is amazing compared to what I had and my milli's are much hairier during the day. The Grim Reefer knows his stuff when it comes to T5's as far as I'm concerned.

[jamesbuf]

I've got to respond before James pre-disagrees with me.

 

 

Smartarse.

[gastone]

Smartarse.

 

 

Ha.

 

G.