Sure re: carotenoids. I was always under the impression that they also act as accessory pigments, extending the range of wavelengths absorbed to drive photosynthesis. As far as the chlorophylls go, based on their absorption cross section, it looks like they absorb more light at lower wavelengths, so I'm not sure what you mean by the ideal level of chlorophyll excitation. Unless you mean the amount of energy transferred to catalyse oxygen evolution? In which case sure... They dump all the excess energy from the higher energy (shorter wavelength) photons off as heat (via internal conversion).

Yes, of course. I was thinking yellow for some reason. Should've had a coffee pre-post.

Are you a biologist, or just an enthusiast? :biggrin:

Agreed. While I tend to go on about missing my MH, these are great alternatives and I would buy them again.

I'm coming around.....seems the shimmer is there with my pendants.... but hanging them over coke cans in a cardboard tank takes away from the experience.

anyone locally have pics of kessil a350 (its the adjustble one...tuna i think) and orpkek dif-100 (growing on me more and more....but i'd need three i think....well maybe two and the kessil....maybe a smaller one. Will allow me to do the spotlighting effect i want....Heard back from my japanese friend i'd need a lot of money to get the MH spotlights i was hoping for....

I've seen the Kessils on a tank and think they're a nice light, but not really giving a spotlight effect.

No I know, the Orpheks do...depending on how you place them...you need a wide tank....they don't spotlight like the MH spots for sure...but I may be able to achieve what I want...the Orphek covers 36 inches if its 12 inches off the tank...give or take....but lowering it :)

I've seen a few pic's where they are put in between other led fixtures....there is defn a spotlight effect to varying degrees going on...but it was a 4 foot wide tank...possibly greater...I'm playing with ideas right now....might need a MH spotlight after all...been awhile might be able to find them in Can or US now i suppose :redface:

We Shall see I guess....was looking online at the new Orphek Atlantiks....$940 canadian....seems interesting but not really what i am looking for.

I own 7 black SOLs, the reason I'm selling one if that I had one over my breeder tanks and I think that's a bit of an over kill for that. So I decided to part with that one only. I have 6 SOLs fixtures over my 240g and they're doing an excellent job at growing corals (mixed reef) and I would not give them up. I'd think about it maybe in a couple of years or so but for now they're great!!

Hey Pan you seem to have done your research on LEDs. This thread has kind of turned in to a discussion on all brands just like the 100 other posts out there. Your not going to have the same look as MHs. The majority of guys that have switched to LEDs are happy with them after some tweaking. It appears that your just trying to convince yourself to try them. Good luck if you do. It's not like you won't be able to resell them. :biggrin: