420nm or 460nm, which one and why?

[Deep Thief]

Hey all, Can you tell me the differences between the 420 and 460nm wavelength (besides 40nm) and which do I want and why? This is kinda blanket questions, as it has implications on several reefs/projects I am working on. I am really more just interested in general answers since I want to use this info across all reefs/projects. If you must know what the particular two projects are, here they are:

 

Project #1

30 gal std tank as a mixed reef.

sps on the top & mid level, lps on the mid & bottom level, and softs on the bottom level and side

150w current sunpod using their 14000K bulb

I am thinking of putting two sets of 2bulb 18w PC's in. I was thinking of spliting one set up to one bulb on each end, this is where I am interested in the 420/460. I will use this as a dawn dusk effect. I have offset my MH slightly to one side of my 30 and will put the other 2 bulbs from the second ballast on the opposite side from the MH. This is more the softie side of the reef. These bulbs will be the 50/50 ones.

 

Project #2

Nano-Cube 6 for my wifes classroom, shes a school teacher.

Currently it has one 50/50 bulb.

The fans don't work and it really doesn't seem to heat up the water any. I have had it running with freshwater as a test. I am now thinking about ripping the fans out, moving the one ballast out and then flatening the felector and adding in another single 18w ballast/bulb combo.

So I am thinking about making these two bulbs, one a 10000K and one an Actinic, Here is also where the 420 or 460 question comes from. Which one to use, as the other one?

 

Thanks much for the help, Mark

[kthehun89]

420 is violet, 460 is blue. its all preference sake. Although, photosynthesis does occur at 460nm but not at 420 (something about absorbtion of the light to chlorophyll). I'd go for the 460

[Deep Thief]

420 is violet, 460 is blue. its all preference sake. Although, photosynthesis does occur at 460nm but not at 420 (something about absorbtion of the light to chlorophyll). I'd go for the 460

 

Thanks for that, if photosynthesis does not occur with the 420 then 460 it is. I am a function kind of a guy, not so much fashion. Mark

[mg4015]

if you have a setup that allows, i would reccomend that you add 420nm pc's to your halide for the 30gal, and off of that add some sunpod LED actinics (using 460nm LED's), built as described in the thread about those. that will give you the finest 460nm actinic lights availible, plus the color enhancing but otherwise marginal 420nm PC bulbs

 

if you cant do that, do just the LED actinics, it is well worth the cost, the result is phenominal. it isnt terribly expensive as far as leds go to do that mod, and is a great starting point.

 

(can you tell ima bit obsessed with led )

[Stircrazy]

420 is violet, 460 is blue. its all preference sake. Although, photosynthesis does occur at 460nm but not at 420 (something about absorbtion of the light to chlorophyll). I'd go for the 460

 

 

the wavelenght range for PAR is 400 to 700nm so photosynthesis will ocure at 420. the only factor in choosing these lights colors is personal preferance.. do you want more purple or do you want more of a blue?

 

Steve

[jtl2]

I don't think corals could survive on 420nm alone, but you could probably say that about several specific wavelengths. The general photosynthetic range is from 400nm - 700nm, just a clarification.

[Deep Thief]

So the choice comes down to astetics? Thats it. Both will serve as my dawn/dusk effect. Which do I like best? Interesting I will have to ponder this.

[davidncbrown]

420 will give your corals more of a pop if they have any sort of florescence to them at all because it is closer to the ultraviolet spectrum. The absorption peaks of chlorophyll a (found in most photosynthetic organisms including zooxanthellae) are at about 660nm and 460nm. So yes, your 460 bulb will provide much greater PAR than the 420, but the 420 still does provide a usable level of PAR. All this aside, if you are just using the actinic supplementation for a dawn/dusk effect then I take it the actinic's will be off during most of your lighting period? If that is true then PAR has absolutely no meaning to you and you are correct it will be purely aesthetics.

 

And a word of advice... get rid of the current MH bulb and get a phoenix, radium, or my personal fav (albeit a lower PAR than the rest) an XM 20K which I have over my nano. The current bulbs aren't the best bulbs out there.

[Deep Thief]

420 will give your corals more of a pop if they have any sort of florescence to them at all because it is closer to the ultraviolet spectrum. The absorption peaks of chlorophyll a (found in most photosynthetic organisms including zooxanthellae) are at about 660nm and 460nm. So yes, your 460 bulb will provide much greater PAR than the 420, but the 420 still does provide a usable level of PAR. All this aside, if you are just using the actinic supplementation for a dawn/dusk effect then I take it the actinic's will be off during most of your lighting period? If that is true then PAR has absolutely no meaning to you and you are correct it will be purely aesthetics.

 

And a word of advice... get rid of the current MH bulb and get a phoenix, radium, or my personal fav (albeit a lower PAR than the rest) an XM 20K which I have over my nano. The current bulbs aren't the best bulbs out there.

 

Planned schedule of my lights would be as follows:

Dawn

Actinics (one on each end of the tank) come on for 1 hour

2-18w 50/50 PC's, come on for 1 hour

150w MH comes on for 8 hours, after the MH comes on the actinics will go off but the 50/50's stay on

Dusk is the reverse order

Actinics come on as MH goes off

1 hour later the PC 50/50's go off

1 hour later the actinics go off.

Night viewing via the blue LED's in my MH fixture, at my leisure

 

As for the MH bulb, in your opinion, whats wrong with the current bulb. I have not actually used this bulb yet. The MH currently has a Ushio 20K bulb in it and the Current was never used so its sitting there brand new. The Ushio is a little too blue for my personal taste and I figured the Current would be more white. That and I don't have to buy another

 

Thanks for the help. Mark

[mg4015]

get a phoenix 14k, dont use the stock bulbs.

 

i would suggest ditching the 50/50 bulbs, and leaving the actinic on full time. that will be a lot of light and heat, keep it to just actinics is what i would do. everything else sounds good

[Deep Thief]

get a phoenix 14k, dont use the stock bulbs.

Why? Thanks, Mark

[kthehun89]

Why? Thanks, Mark

 

the stock bulbs are pretty bad, the phoenix puts out awesome color and par. I have a phoenix and my corals responded amazingly well to it.