DIY Lighting Scale

[jman785]

Light Spectrum Scale and bulb comparisons
by Jared Waites (jman785)

Many problems with hobbyists, is they don't understand what they are buying. They know it grows coral and algae well..but don't really understand the whole aspect of choosing a good bulb. There are two things, to consider, when purchasing a bulb, I'm not really going to focus on one of them, wattage, I'm focusing on Color Temperature and the comparison of the bulbs. Metal Halide bulbs, should usually be placed, every 24", a perfect tank for a halide, would be a 2'x2'x2' tank :) Perfect exposure to light, I am blessed enough, to have a tank with these dimensions.

The 'K' at the end of the color rating, stands for Kelvin, which measures color temperature. The higher the Kelvin, the more cooler (bluer/actinic) the color of light given off by the bulb.

6500k = yellow tint to the color of the light such as the Iwasaki bulb. - Great for growing, although doesn't show coloration of corals as well as the others, but offers excellent growth.

10k - in between 6500k and 20k, great all out coloration and growth, not as good of coloration as 20k, and not as good of growth as the 6500k offers.

20k - not as good growth as the 6500k, but offers maximum coloration and is more blue.

I made this article to help people decide what they want to do with their tanks. 6500k is mainly for grow-out unless supplemented by actinic, or 10 or 20k bulbs, to add more blue coloration to the tank.

6500k is also the closest to natural sunlight you can get, with the good growth it offers.

Iwasaki - 6500k
Ushio - 10k
Sunburst - 12k
Radium - 20k

http://www.marinedepot.com/IMD/lt_mh_bulb_comp_12vs10.jpg
http://www.marinedepot.com/IMD/lt_mh_bulb_comp_12vs65.jpg
http://www.marinedepot.com/IMD/lt_mh_bulb_comp_10vs65.jpg

Alot of this information, can cause heated debates, although from many experiences, by myself and others, I believe this information to suit you best, and hopefully you'll understand more about the bulbs, after reading this, and it can help you make a better selection in the future. Good luck :)


Pictures by N. Morris

Thats Helpful. Wish I Would Have Saw This Before I Got All My Lighting

[jman785]

Well if you ever upgrade, be sure to check it out :0)

- Jared

[Condiman]

excellent info I will keep this post in mind

[Zack]

excellent info I will keep this post in mind


Ditto!! thanks a lot! :)

[Charles Poole]

Where did you get your growth rates vs color temperature info from?

[Telco Guy]

Yes, that would be interesting to know. I'd like to see this topic expanded on with more information about growth and other aspects of each light color and possibly going in to VHO and CF lighting. This could be developed in to a good article for the reference section. :idea:

[pszemol]

6500k = yellow tint to the color of the light such as the Iwasaki bulb. - Great for growing, although doesn't show coloration of colors great.Are you talking about corals colors? I ask because your "blue" tang is very pinkish under any other light... It is really blue only under 6500K on your pictures.

[Charles Poole]

I think it was a typo. Thanks for the pictures. It helps to see what you are talking about... :)

I can give this advice about URI Actinic White VHO bulbs. These bulbs should have a "pink" hue to them. If they look very white or have to visible pink hue, then the bulb needs to be replaced. I run 960 watts of VHO on my 125 gal. I also run a 20 gal with one 175 watt 14000K MH. I get faster growth from the same species corals in the 20 gallon than I do in the 125.

But if you have ever seen what a tank with VHO bulbs looks like, then you know why I have to keep running them.... :)

[jman785]

I've missed the information posted here, I'll have to respond later, as I'm packing for a trip, to Orlando. I'll be able to check it there, and respond to your questions..sorry dudes :)

[jman785]

I'll respond really quick about this.

I've been in the hobby for a long time, Chuck, plus reading MANY articles on propagation of corals and what not...and the 6500k, has given some of the best results as far as growth goes.

The 6500k, has a yellow tint to it as you can see, and its not really actinic looking, as the 10-20ks are...if I didn't answer your question properly...rephrase it and I'll check it, while on vacation.

[Charles Poole]

Interesting.... I have found that the majority of species I keep, tend to do better with increased amounts of Actinic lighting. From my research, 6500k by itself will likely promote algal growth of the nuisance type. I am awaiting Steve Tyrees latest book on SPS corals, which will have a very indepth section on color temperature and intensity. Here (http://www.reefs.org/library/talklog/s_tyree_060202.html) is a link to an abstract of this section written by Steve.

I tried the 6500k MH and Super Actinic VHO combonation on my 125 gallon, and was just not impressed with the extra algae control I had to perform, as well as lower than present growth rates. I guess this falls into the "what works for one tank, doesn't neccessarily work for another." :)

[jman785]

Could be...but it has a lot to do with what tanks are for....beauty, or propagation or both. That's the key to having good lighting...because if your propagating, and you want excellent growth, you could use natural sunlight, or 6500k...if you want good growth, and beauty, I'd use 10k or 12k....but don't get me wrong...I'm not saying, you can grow corals with a 20k bulb, I'm saying, there were studies being performed, by a lot of different experts, that state, that the Iwasaki 6500k, has given the best result on growing coral. Although, you are right Chuck, it really depends on your system...and what it is used to, if you go from PC to MH, you are going to have to gradually expose it to the MH, I'd just use a set of chains, and once a week, for 4 weeks, I'd bring it down, and do this for the next 4 weeks....until its at an adequate level...this enables the corals to adjust themselves to the changes in spectrum and light intensity.

[jman785]

T5 Lighting, is good for tanks...actinic from T5 lighting, is awesome.

- Jared

[Charles Poole]

I have not had the opportunity to view any T5 lights yet. I want to setup a 20 gallon long tank using T5's, but that will be a few months down the road. Do you know off hand if an IceCap VHO ballast will power T5 bulbs.

I have one that will be replaced with MH's soon, so if I can use it, that will reduce the overall cost, and allow me to set things up sooner. I already have the tank, just need a couple other things before I get it setup. Like finishing the setup og my newest tank (75 gallon) Lagoon reef.

The other issue I was concerned with in reguards to the 6500K light is that Saltwater rapidly cuts back the red, yellow, and some green spectrum in NSW. Only the shallowest water species of corals would be acclimated or possibly capable of adjusting to the increased amounts of Red, Yellow and Green spectrums. Since the average depth of most corals in our tanks is around 6 - 12 inches, very little reduction of these colors would be taking place.

Have you run grow-out tanks under 10000K or higher lights for more than 1 year? If not, it would be hard to compare growth rates between these color temperatures.

Did you read the link to Steve's article that I left in my last post? It has some really good info, and maybe I misunderstood some of what I read.

I am very interested in your thoughts on his article. :)

[jman785]

Charles,

I've been stray from this thread for a while, but yes, in the past I have compared growth rates for over a year and that is what I've come up with, as well as many other reefers around the world. Although you still receive great growth from 10k-20k, 6500k (Iwasaki), has offered the best growth for me and my corals.

[Charles Poole]

What are your thoughts on supplementing the 6500K bulbs with actinic fluorescents?

[jman785]

I think it they still look yellow and nasty. Unless you can supplement with another halide ;)

I'm sorry for the late reply on this one. WOW! :lol:

[cich1]

THE 6500K does look to yellow for my taste, i think i like the look of the ushio 10,000k best which is a good thing since i'm getting ready to set one up on my 29g

[jman785]

The 14K is what I finally stuck with...I'm tired of supplementing with other actnics.

[cich1]

i do like the look of the 14k but since i have the 10k ushio and 2x32w actinics thats what i'm going to use till bulbs need replaced, btw Jared I started on the canopy last night so maybe i'll have the mh up and running by next week

[jman785]

Good deal man....

Can't wait to see it.

[MoonSoft]

A lot of debate over what color looks best, i have found that some of our cusstomers (mainly coral farmers) and aqauculture sites, seem to be favoring a 6500K / 20K spectrum get the growth out of the 6500K bulbs and get the color out of the 20k's, i have heard that even then they like to supplemet with actinics, said they get better color developement, but from the growth standpoint, i have to ask
What growth are you measureing? soft corals?
Hard corals?
coraline algae?

The reason i ask is that each of these animals users a different nutrient base for their growth and to surmise that a bulb offers better growth is pretty brao answer, i mean i have seen my iwasaki bulbs inprove growth.... of ALGAE.... but thats my system, before i overhualed it.

I gues what i boild down to is what part of a reef are you trying to replicate.. plenty of people out there just put their reef together with whats available at the LFS and what they like.. with no attention to where these corals thrive on a reef system.

Example:
1) Table acropora, top reef anywhere from 2-35 feet on the reef
2) brain corals super highflow and about 40-70 feet
just with those two examples the lighting spectrum is really different
brains typically do better in higher kelvin light whereas top reef corals seem to get better growth using 6500k spectrum up to 10K i could be wrong but i have found targeting what i want to keep and then replicating the spectrum seems to work best for growth... if i started putting softies in my tank i would expect to see them shrivel up and die!!!!!

[jman785]

The PAR rating of the bulb is also something else to consider in this situation. I'm referring more to propagation tanks, rather than display tanks here, unless you supplement with another halide, rather than actinic NO's, or you could go with VHO for supplementation.

We've been conducting studies with those bulbs at the Gulf Coast Marine Specimen Laboratory and have found the 6500K (Iwasaki) to offer the best growth rate as far as Acropora's go, and with most softies. We are talking 16 inches of water with no substrate as well.

[MoonSoft]

Thats really amazing i would wonder what wattage of bulb and style i would be interested in ising a iwasaki 6500K if they offered it in DE style

[jman785]

I do believe Mogul (Screw-In) is the only type of Iwasaki available...and the bulb wattages, were ran, all of the bulbs were testing and all of their wattages...I currently run a 400W Iwasaki at work for propagation, and I run a 400W 14k Hamilton on my display.

[MoonSoft]

Got a question for you have you noticed better growth with that 6500 supplemented with actinics or just the 6500 alone?