Is 20k enough actinic

Okay, so I know a few people (myself included) who are using 20k halides.  I don't think any of us are also adding actinic light.... right???? 
Do all you 20k users think you have enough blue light?  And do you think you have enouh white light?

Adam

We have silver Aquaspace lights.  There are 2 of them, each 48" long.  Each has 2 x 250 watt 10k d.e. metal halides.  Also included are 2 x 24 watt blue power compacts. 

After watching the lighting demonstration, it seems like his opinion was that the amount of light was not the most important factor, but the distance of the light from your corals.  Did I misunderstand?  Also, the reflector seemed like it was important to the intensity.

Lighting is one of those things that I wonder if we have too little of.  These were $850 each.  I think the cashier thought I was going to pull out a pistol & run away when he told me the total price with tax.  I'm not sure if we have enough light.  Some guy named Adam said, "You can never have too much light." 

Can't wait to see what everyone says!

Travis,

Ding*

Possibly the best question I have read on this forum for months.

Adam

Adam -

I have a couple VHO's with my 20k's now. One that is a 10k (which is pretty much pink as far as looks go) and a actinic. I think the actinic helps to make up for the totally pink vho. I wasnt getting enough yellow/pink out of my coral, so I added the VHO's. I have been kicking around adding more actinic though - maybe some PC's.

I would say... well for both.

Then the only answer lies within you & your tank.  As a general rule I would say the spectrum that produces the most par would be the most beneficial to the corals... everything else is preference.  Of course if someone has a 400w bulb on a 20g tank that's not going to be an issue because even the lower par spectrum's would most likely be enough for any coral.

I seriously considered the 20k until I found out the par that is lost going from 10k to 20k.  In my tank I think the additional par from a 10k is beneficial.

I'm currently running 2- 10k MH with 2- actinic VHOs.  I wouldn't mind more actinic (I really like the bluer look) but IMO the corals look good and have a nice growth rate. 

I remember seeing that the par difference on the XM bulbs was something like 250ish PAR for the 20k 150W and 400ish PAR for the 10k 150W.

How far apart are you two halides BTW

Yes, I think you might be simplifying . 

PAR is a measure of the amount of light in the photosynthesis range.  400 nm to 700 nm.  Here is a chart showing photosynthesis rate vs. wavelength for "normal" plants.

Notice the peaks in the blue and red.  And there is essentially no red light after traveling through just a few feet of water.  Everything's shifted to the blue.  Corals have adapted to use blue light.  Do they even have the right photo active pigments to absorb the reds?  I don't know (I'm still researching), but I think it's an interesting topic of discussion.

Back to the bulbs... looking at the spectrums, I'd say even though the 10Ks appear yellowish/white, they still have as much or more blue then the 20Ks.

Here is a chart showing photosynthesis rate vs. wavelength for "normal" plants.

I see...  no clue but I understand the question now .  From what "little" I know about it, I think corals could adapt to using the full photosynthesis range.  I posted an article on this a while back but the article was very 'preliminary'. 

Maybe I'll try that.  I haven't had a 10k bulb, but I saw a tank with a 10k on one side, and a 20k on the other.  I'll post pics tonight.
With my canopy and reflector the way it is, I was thinking of mounting them _-_ like that with the 10 in "center".  But I could try -l- instead.  Hmmm, something to think about.  My real question I guess is do I add another halide, or use two pc/vho type of bulbs?

Always changing my lights.... have been for 15 years.... will I ever be happy and stay with something?

Adam