Let's talk T5's

I currently have a CadLights 50 cube. I'm running a 24" Coralife 4 bulb w/ lunar LED'S. After watching John Moss' presentation the other night I have a few questions?
I originally set up the bulbs in this order (all ATI bulbs) :
FRONT
Blue+
Coral+
Purple+
Blue+
BACK
But in an effort to hit the lower end of the blue spectrum I changed the bulbs to this:
FRONT
Blue+
Actinic
Purple+
Blue+
BACK
So I guess my questions are:
Is it possible to cover the spectrums needed for LPS/softies towards the bottom, SPS at the top with either of these light configurations?
Is it possible at all, with a 4 bulb t5 unit without supplementation?
What's the best 4 bulb combo for both coloration and growth?
Am I losing out on a critical spectrum by dropping the coral+ bulb?
Thanks in advance!

Tank is 20" deep. Using the standard tank mounts/legs, I'd say about 4-5" above the water surface.

ReefdUp, you're correct on both accounts. Neither combo bothers me visually. I guess I was just in search of the best combo for growth and color. I'll pick up another Blue+ bulb this week and try your suggestion. Thanks for the info!

+1 that most aquariums are too shallow for spectral reduction to be an issue. The light at the top is generally the same as the light at the bottom, albeit more intense.

I love ATI T5's. Great lighting decision. As Nikki said, tested and proven. So I won't even bring LEDs into the discussion.

I'm still a huge supporter of boosting the near-UV range, as it is almost as important to chlorophyll absorption as the red end of the spectrum. I think most lighting solutions are lacking in this important part of the spectrum. I don't have the scientific data to back that claim for now, although preliminary analysis has been positive.

By switching the Coral+ to Actinic you are sacrificing red spectrum for near-UV spectrum. Would this give you a noticeable difference in growth? I for one would be interested to find out. I'm going to throw out a hypothesis that you would actually get slightly better growth and coloration with the Actinic bulb. Here is why:

The ATI coral plus bulb's red peak is more in the amber spectrum ( ~620nm ) where the chlorophyll absorption peak is closer to 670nm. Chlorophyll is also very picky when it comes to the red spectrum it likes, it dives off quickly on either side of 670nm. So the 620nm peak in the coral plus, theoretically, is less useful than the large spectral range of near-UV that the actinic bulb provides.

If you look at the graphs below, you can see that the coral plus's amber peak misses the Chlorophyll-A absorption peak by quite a ways. Chlorophyll-B does have a peak in amber, but it's smaller in relation and Chlorophyll-B is much much less common in corals overall than Chlorophyll-A.

CHLOROPHYLL ABSORPTION



Edited by Pete Moss - March 09 2015 at 4:33pm

Skulldozer wrote: Awesome John! Thanks for taking the time to respond. This community is awesome. As for now, I'm going to keep the actinic bulb. I'm really liking the blue and the colors. I'll keep you updated on any growth or color changes.

Awesome, take lots of pictures along the way! If it flops you can blame me hahahaha

Edited by Pete Moss - March 09 2015 at 4:14pm

You guys know way more about this than I do! Let me know what you guys decide! Haha!

Sorry...my thesis in the real world (#2...glutton for punishment, I know) got in the way. This is more of an interesting topic though. :(

In my opinion, which is not necessarily scientific, just listening to experts over the years and my own trial and error, the second combination(posted above and copied below) supports the best growth and color.

Well, I'm starting day 4 with the actinic combo and I'm still getting full polyp extension and the colors have never looked better. Growth is obviously TBD, I guess time will tell?