Better Growth&Color; PAR or Kelvin Rating?

[AaronP]

In order to get better growth and color for sps, is the amount of par in a bulb, or it's kelvin rating more important?

My dilemma is that I really like the color of a 20k bulb, but I don't want to sacrifice the par that I could get with a 14k or 10k bulb. This is what I have come up with: I could upgrade my lighting from my originally planned 250w to 400w. That way, it will be easy to find a 400w 20k bulb that easily has more par than most 250w 10k and 14k bulbs.

Now, I know that with a lower kelvin rating, of course there will be more par, and that lower kelvin rating is recommended for better growth. 10k bulbs are recommended for better growth, but is this because of the high par rating, or because of the color spectrum? In other words, can you get better growth and coloration with a 20k bulb that has more par than a 10k bulb?

 

[Reefer420]

whats the size of your tank?

 

[House of Laughter]

Both, Par for color (and kelvin for secondary color) and kelvin for growth.

House

 

[Reefer420]

Both, Par for color (and kelvin for secondary color) and kelvin for growth.

House

House- I had always thought that Par was the intensity of the light while Kelvin was the color...

So you could get the best of both worlds w/ a higher wattage 20k bulb?

 

[AaronP]

Exactly my question Reefer.

So house, your saying that the lighting spectrum for the lower kelvin rating bulbs is really what you need for good growth?

 

[Aqua Pro Builder]

Higher par will do good to both but it will also fuel other living organisms in the tank which could be good(macro grow faster) or bad (green algae and cyano). Yet, higher temperature associated with high par may bleach out your corals. My experience with 2 candy cane frags(from the same colony) in 2 10G tanks SEEMS to indicate higher temperature will cause the candy cane to have washed out colors. However, the experiment is too simplistic to have any real conclusion. You have to find the balance by observing your tank for a long time to tell.

As for kevlin, it will not affect your coloring of the coral unless the wavelength of a 20K is exactly what the zoxanthelae alage within the coral needs-I do not have the wavelength info of a 20K, so can't help you in that. Higher K only gives you eye candy when you turn it on.

 

[Reefer420]

by color of the coral i'm taking it to mean the natural coloration and not the overal look of things in the tank, right?

 

[House of Laughter]

Wingo, I am sory but you are dead wrong - kelvin is the color emitted by the bulb - take a standard 10k bulb an start a coral close to the bulb - you will get high growth and may get washed color depending on the coral.

Lower that same coral down a foot under the same bulb and see the difference in the color.

Par DOES = growth but good par and the right kelvin will color your corals like no other.

House

 

[ezee]

Aaron,

House- I had always thought that Par was the intensity of the light while Kelvin was the color...

So you could get the best of both worlds w/ a higher wattage 20k bulb?

This quote may be accurate but I would urge you to be careful. Just recently I saw a beautiful tank that switched from 250s to 400s and experienced bleaching, according to the owner. There were some other considerations, of course, but just be careful when you transfer over. Acclimate the corals to the new light very slowly.

It is a generally stated belief that wattage is a reflection of depth but it could probably work. Although you may get better growth there are other things that become concerns. For one, 400watts is hot!!! Of course, there are many more experienced reefers here that may have already tried this and can give you better info.

BTW how big is your tank?

E

 

[ezee]

Aaron,

Ooops just realized you are not currently running even 250's yet. My bad.

E

 

[Aqua Pro Builder]

Wingo, I am sory but you are dead wrong - kelvin is the color emitted by the bulb - take a standard 10k bulb an start a coral close to the bulb - you will get high growth and may get washed color depending on the coral.

Lower that same coral down a foot under the same bulb and see the difference in the color.

Par DOES = growth but good par and the right kelvin will color your corals like no other.

House

What part of my view is not the same as your quote? :scratchch :scratchch :scratchch

Everything you said above is same as my views!

Did I choose the wrong words or something in my original post that misleded you? :scratchch :scratchch :scratchch

 

[Reefer420]

Aaron,



This quote may be accurate but I would urge you to be careful. Just recently I saw a beautiful tank that switched from 250s to 400s and experienced bleaching, according to the owner. There were some other considerations, of course, but just be careful when you transfer over. Acclimate the corals to the new light very slowly.

It is a generally stated belief that wattage is a reflection of depth but it could probably work. Although you may get better growth there are other things that become concerns. For one, 400watts is hot!!! Of course, there are many more experienced reefers here that may have already tried this and can give you better info.

BTW how big is your tank?

E

Well my tank will be 37g - the tank is 21" deep and the lights will be 10" off the water. I was thinking about a single overdriven (by an HQI ballast) Radium 20k bulb - but I'm just worried about the light giving enough growth since 31" is pretty far to the tank bottom. I think 400w is way overkill though (and too hot..)

Going back to the original topic question- I'm pretty sure from what Ive been reading 250w has more 'punch' than 150w to get more penetration in depth, so 400w should have even more, right? So I guess that you shouldn't go by total gallons - more like tank depth and the width the bulb has to cover (something like a 24" square per bulb), right?

On that note- could you go w/ a 20k bulb in a more shallow tank to get the same kind of growth you could w/ a 10k bulb in a deeper tank? Or is it more the wavelength of the light that gives the growth and not how intense the light is...:scratchch

 

[ezee]

Hey,

Well my tank will be 37g

Wow. A 400w on a 37 is kind of extreme. I really think it is overkill, the 250 hqi's might even be a lot for that size tank. Do you have a central brace or is it euro?

E

 

[Reefer420]

I'd be using a 20k SE bulb- so not quite as intense as an HQI. Its a semi-cube Oceanic, so no bracing.

Since I want to build a canopy on my tank, I'm thinking the bulbs are going to be 10" off the water. The tank is 21" deep- making around 31" of height from the bulb to the sand. I'd go 150w HQI if I was going to use a fixture only a few inches from the water...

I've been doing a lot of tank searches- saw a bunch of 30g Oceanics w/ 250w SE MHs over them, with good success and a mix of corals, so I'm thinking as I want to keep clams 250 is the way to go..