Metal Halide Lighting Scale

JaredWaites · #1 01/03/2008, 12:33 PM

Light Spectrum Scale and bulb comparisons
by Jared Waites

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 and that's 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 for testing stuff.

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. Excellent PAR rating as well.

10k - in between 6500k and 20k, great all out coloration and growth but 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 actinic 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

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

FishF00d · #2 01/03/2008, 02:24 PM

this topic is very debatable. I've seen great colors from lower K bulbs. To me the 20K make everything blue-green where the lower K (10-12) help bring out the Red, Orange, Yellow colors.

Thus IMO if you are going with MH i would suggest going with 10-12k and supplement with T5 bulbs on the higher end of K, although there are a some bulbs that claim they are the 12k range but also seem really blue.

DrHank · #3 01/03/2008, 04:37 PM

Interesting but it looks a lot like this:

http://archive.reefcentral.com/forum...hreadid=254667

Are you saying that your are the source of the information and photography? Your by line leads me to that conclusion but the 2003 post would seem to contraindicate that. It's good information but I do like to give credit where credit is due.

Just wondering as it looks so similar to an earlier article.

JaredWaites · #4 01/04/2008, 09:28 AM

No, my photos were taken by N. Morris and he was contracted by Marine Depot.

And I gave credit if you look up at the post it says 'Photos by N. Morris'.

All the text write up is mine from when I used to post at Coral Forum and a few other places I have it at. I edited a lot of the information as I was in a hurry when I wrote it for Coral Forum...but there are a few more articles that I wrote for CF that I'll post over here.

Actually JB NY thread is a little more detailed then mine was...mine was to simply help you compare Kelvin colors and growth rates...to be able to say hey I want that bulb, because it'll suit my application better than this Radium 20K that my LFS is trying to sell me.

He also includes PAR rating and Amps, which I don't.

DrHank · #5 01/04/2008, 11:41 AM

There is also some good information available on 250w SE bulbs that Sanjay Joshi wrote a few years ago with good bulb/ballast/par information. Unfortunately there isn't any accompanying photos but there are graphs.

I think lighting will always be a controversial subject. Since I use conventional magnetic ballasts, I'm probably going to move to XM 10Ks replacing bulbs 2 at a time starting in a month or so. I'll replace pairs at 6 month intervals moving the new bulbs to the center.

JaredWaites · #6 01/04/2008, 12:23 PM

10K seems to be the norm for a lot of people.

Most 10K bulbs offer great coloration without the need for actinic supplementation.

I think they'll look nice on your tank Doc.

Sanjay has a new page now I think and you can compare the lights and ballasts btw...might try to Google for it if your interested in some more reading.

FishF00d · #7 01/04/2008, 01:37 PM

The XM 10Ks were a little too yellowish for me by themselves. I'm sure you have VHO or T5 actinics though so it shouldn't be a problem. Lots of people seem to get good color with the XM 10Ks as well. I'd probably go with them if i were going to add MH back on the tank. If anything I will just add more T5 and see how that works out. I'm not the biggest fan of all T5 at this point but I also have a pair of VHO on as well.

DrHank · #8 01/04/2008, 01:58 PM

There is a lot to be said for T5s but I've never seen the T5 actinic that will come close to VHO or even PC. Also, I miss the shimmer that you get with MH.

JaredWaites · #9 01/04/2008, 02:20 PM

Doc,

You are dang sure right about just having fluorescent lights...you miss out on the shimmer.

I've heard you can overdrive T5's though to get the output comparable to VHO...but of course with this you'll have shorten lifespan of the bulbs I imagine.

jadeguppy · #10 01/04/2008, 03:29 PM

Grim reefer has an awesome post about t5 lights. Icecap ballast overdrive them. I wish I had the light ready for you guys, but I ran out of $$ in favor of buying for others during the holidays. I will probably but on a 4 bulb combination that grim suggested. I like the avalibility of different combinations with them. The individual reflectors also make them much more effective than single reflectors.

DrHank · #11 01/04/2008, 03:42 PM

Grim seems to know quite a bit about T5s and he'd be the one I'd ask if that was the way I chose to go. The correct set up with individual reflectors and overdriven ballasts will get you PAR in the MH range. IslandCrow (Mike) had a very nice retro set up and it put out some light.

I missed two things when I ran them on my 110. The first was the shimmer. I find that I just have to have the shimmer. The second was the blue. Eventually either VHOs or PCs will supplement my four MH bulbs and provide the blue I like.

It does cost a bit more to run, I'll have to be changing two of my four bulbs every 6 months, and I'll have to hook up the chiller soon but to me it's worth it. I want my tank my way. Fortunately, my wife loves the tank too so it's never a question if, just when.

lobstergrabber · #12 01/04/2008, 03:50 PM

Are the xm 10k's similar to the Ushio 10k's? I was amazed when I bought my phoenix 14k's. Still white but with a definite blue tint and then my 2 110 vhos. Made for a color very appealing to me anyway. Wish I had taken pics with one 10k and one 14k to show you the difference. I have 250 watts double ends with ice cap electronic ballist though so don't know about the difference just thought I would throw the idea out there and give you one more thing to think about.

Rich

DrHank · #13 01/04/2008, 03:59 PM

If you are talking about comparing 250w 10K SE bulbs, the XM produces significantly more PAR that the Ushiro. I use standard magnetic ballasts. With them the XM was rated at 698 and the Ushiro at 485. The XMs put out a lot more PAR than the 14K Hamiltons I'm using now too. Hence the reason for the switch.

I've never heard of anyone complaining about coral growth with them either. Actually, just the opposite.

JaredWaites · #14 01/04/2008, 04:02 PM

Normally doube-ended halides seem brighter than a single ended setup.

Rich,

XM 10k's are slightly more actinic than Ushio 10K's.

Hamilton makes a great 14K bulb btw incase your set on a 14k bulb. It's almost enough to my liking to get rid of actinic supplementation all together!

Edit: Me and Doc must have posted at the same time...I didn't look at the par ratings...wow that's a considerable difference that Doc has noted above

FishF00d · #15 01/04/2008, 04:06 PM

I had 250w 14k SE Hamiltons and never did really like them. Then I changed over to DE bulbs. I went through a bunch of bulbs and have to say I liked the XM 10Ks with supplements the best. The Phoenix 14k were ok when I wasn't running any supplemental bulbs but I didn't seem to get much growth.

DrHank · #16 01/04/2008, 04:10 PM

I'm running 14K Hamiltons on my big tank and really liked them at first. After six months, and ont bulb burning out, I'm not as happy with them as I once was. My birthday is coming next month and I think I just may wind up with a couple of XM 10Ks.

JaredWaites · #17 01/04/2008, 04:15 PM

Yeah I did notice the bulb showing some considerable degradation over a 6-8 month period. That was one downfall to the color of the Hammie's!

JaredWaites · #18 01/04/2008, 04:18 PM

fishf00d,

I looked at the your post above...you won't great growth rates with anything higher than a 12k. I mean you will get some...but nothing like you can get with a 6500K or a 10K.

FishF00d · #19 01/04/2008, 04:25 PM

Others here on RC had said there were getting decent growth with them and had the pleasing blue-white color. I tired out about 5 different DE bulbs over the last few years starting with the Megachrome 13k, which I liked but it was on the expensive side so I looked for other options. I think over that time I also had XM, Phoenix, Ushio, and I think there was another 1 or 2 I tried.

In all I actually had a brighter tank with most of the SE bulbs than I had with the DE bulbs. It probably had to do with the type of reflectors. I had the Reef Optic III's which didn't give you too great of coverage.

JaredWaites · #20 01/04/2008, 04:58 PM

Yeah I read that you get great growth with them...but I never could even compare the growth of the 14K to the 6500K's I was running.

They are yellow as hell though...so you will need some actinic with the 6500K's if you do decide to go with them in the future or whenever.

SWINGRRRR · #21 01/05/2008, 12:55 AM

I am thinking I am going with 1 XM 10K, and dual 96 watt actinics for my tank.

60Cubed · #22 01/05/2008, 01:55 AM

I like the Reeflux 10k. They are a little on the white side. However, if you have VHO supplementation, the color blends together and it looks good. Plus....... they give awsome growth to boot! These were of course 400w 10k's.

I once had a 75g with two 12k 175w and one 6500k 400w halides. I had the two 175's on each end with the 400w in the center. I turned the 175's on first and last with the 400w on for about four hours. The 175's were on for 10 hours. I had the best growth in that tank than any other tank since.

Just my $.02

FishF00d · #23 01/05/2008, 02:06 AM

I had both the Reeflux 10k and I think 12k bulbs as well, DE. I can't remember what they looked like.

Lance.. Your 400's are going to always make things grow a little faster. I myself wouldn't ever use a 400, unless I have a super deep tank. Too much money and I've seen just as nice tanks with 250's that I can't see trying to fight the heat issue.

SWINGRRRR · #24 01/05/2008, 02:56 AM

Drew how deep is your tank??
I am torn between going with a single 175 or a single 250. My tank is 24" deep with a shallow sand bed.

JaredWaites · #25 01/05/2008, 12:06 PM

Just go with the 250. I think you'll be happier in the long run. Don't skimp on the reflector either and you can make it worth your while. Either buy a Lumenarc III, or check out the DIY forum for the Lumenarc DIY. I've actually got the plans somewhere on my PC.

They are trying to prove now that you can achieve the same amount of growth with a 250W vs. 400W in the same amount of space...which I believe to be true. I am running the 400's because I already had them.