Robb D.

I am going to upgrade my current lighting which consists of 2-175W, 10,000K Metal Halide to 400W. After checking the available options, I see that if I plan to use 6500K Iwasaki bulbs, the ballast is specific to those bulbs, and if I were to use 10,000K I could use a standard ballast. I have a 120g that is 24" deep, and am planning the upgrade to support life with SPS corals and clams. After additional research, I am finding that the K (color temp) is a decision which is appealing to my eyes, but which color temp is most desirable for the animals I plan to keep? I guess I am looking for feedback from the group as to which bulbs most have used to keep the animals I plan to keep, and which bulbs/ballasts fellow groupmembers are using. All input is appreciated.

N

I am going to upgrade my current lighting which consists of 2-175W, 10,000K Metal Halide to 400W. After checking the available options, I see that if I plan to use 6500K Iwasaki bulbs, the ballast is specific to those bulbs, and if I were to use 10,000K I could use a standard ballast.

That "special" ballast for the iwasaki bulbs is a mercury vapor ballast, if memory serves. That ballast happens to be a good combination with that bulb, producing the highest output and best spectrum. If I recall correctly, you could indeed use a standard ballast with a 400w iwasaki bulb, it just wouldn't produce quite the same quality/quantity of light.

I have a 120g that is 24" deep, and am planning the upgrade to support life with SPS corals and clams. After additional research, I am finding that the K (color temp) is a decision which is appealing to my eyes, but which color temp is most desirable for the animals I plan to keep?

The color temperature that most closely approximates the original environment where the animals in your tank comes from. That being said, you (like many of us) probably have (or will have) animals from a variety of environments, which would probably require a variety of color temperatures -- or some adjustment to different conditions on the part of the animals. All lighting systems either require compromises of some kind, or a huge skylight in your home :)

I guess I am looking for feedback from the group as to which bulbs most have used to keep the animals I plan to keep, and which bulbs/ballasts fellow groupmembers are using. All input is appreciated.

Having asked a similar question some time ago, as I recall the 400w/6500k iwasaki with mercury vapor ballast you mention is preferred by those who want to closely simulate normal daylight. There are quite a few folks on this list who keep SPS animals under those lights with great success.

The 10000k lamps (any brand) are going to put out more blue spectrum, such that the overall effect is a whiter light than the 6500k lamps. That color is more pleasing for us humans, but as I recall it really doesn't do much for corals! It's just aesthetic value that makes some folks opt for 10000k color temp bulbs.

Personally, I struggled with this same decision some time back, though I was considering the 150w/6500k iwasaki's, not the 400w versions. I ended up going for ice cap electronic ballasts with 175w/10000k ushio lamps for my 48x18x25 tank. I decided I wanted to please my own eyes (and keep my wife from complaining about a yellow tank) instead of going for a slightly more natural spectrum. My animals have responded well to this light, though I do kind of wish I'd gone for the 250w versions.

Near as I can tell, I think the greater output of the 400w lamps will do more for your animals than what color temperature you end up choosing. Make sure you use a good reflector to capture all of that output too.

Trevor Bigot

The Iwas do run to spec on the mercury vapor ballast. There is no other 400W bulb/ballast setup that compares to the output of this combo. Downside is you can only run that bulb. I'm running two over a 90 now and can't convince myself that they aren't yellow (btw the MV ballast does make the bulb burn whiter than a MH ballast). I'm switching (for now) to Radiums (20K) on a pulse start ballast.

This topic has been discussed at length on various reefing bboards. As you can guess, there are very few things people will agree on when it comes to lighting. What it boils down to (IMO) is what looks good to you. Most if not all of the 400W systems will provide a tank your size ample light, and your livestock will most likely thrive as a result. If I had to guess, I'd bet that most people are running 10K bulbs with actinic supplementation.

Didn't help much, did I...

Mike Kirda

After additional research, I am finding that the K (color temp) is a decision which is appealing to my eyes, but which color temp is most desirable for the animals I plan to keep?

There is not a single person on the planet who can answer this question with anything other than anecdotes and opinions.

To answer the question would require an immense amount of work, more money, and a lot of space. The scientific community has absolutely zero interest in doing the experiments required, unfortunately. I see no real answer to this question anywhere on the horizon either.

Richard Harker has started on experiment with very limited numbers of coral frags under two different MH bulbs. His work has just started. One issue that came up almost immediately was that he was working with only an N of 1 for each species. In other words, one frag of each coral under the two bulbs. Because of the variability with which frags grow, this number is too small to run any statistical analysis on. Hopefully, he will restart the experiment with a larger number of frags, a number large enough that the numbers can become statistically significant.

Bob Denton

Is PAR a function of color temperature or of some quirk in bulb manufacturing? If one was looking for a bulb that was the "most desirable for the animals" would the one with the highest PAR be the winner? (Maybe 6500K Iwasaki bulbs?)

Mike Kirda

PAR stands for Photosynthetically Active Radiation.

Essentially, the wavelengths were photosynthesis can occur, which corresponds to wavelengths between 400 and 700 nanometers.

Because what we 'feed' with the light is the zooxanthellae, it makes sense that we are mostly concerned with this sub-spectrum.

Any bulb that gives off light in this range with sufficient intensity should satisfy the photosynthetic needs of the corals. Given the few animals we do have this information on, if I were going to keep higher light loving animals, i.e. Tridacna clams, I would shoot to have levels of at least 250 micro-Einsteins/square meter at the bottom of my tank.

Now, I personally use Iwasakis. I recall them having the highest output of any 250W bulb, but do not have the info in front of me. Personally, I do not think that the corals will care what color temperature is thrown at them, as long as they are given sufficient intensity and have a spectrum that reasonably approaches sunlight, or u/w light. In other words, do not try a really, really bright red light...

Otherwise, most of the bulbs sold for the trade should work fine.

Michael Raffa

Here's Sanjay data on the 250W 6500K Iwaski bulb, expressed as PPFD
Magnetic - 124.3
Mercury Vapor - 106.5
IceCap - 99.8
E-Ballast - 90.7

Robb D.

Thanks all for your subjective opinions - they have been helpful in basing my own decision on the upgrade. I am now going to ask for another opinion - what are the negatives of using an electronic ballast vs. a core & coil design? I understand the main benefit being that the e-ballast is considerably more energy efficient, but I have not heard of any of the cons.

Steven Bielamowicz

Mike Kirda

what are the negatives of using an electronic ballast vs. a core & coil design?

They are not exactly waterproof.

Not meant as a joke- My tank suffered a catastrophic failure. The crack was on the bottom of the tank, and a great deal of water seeped through before I finally had it empty. The ballasts (tar) had had a salt water shower. They still functioned fine when I tested them after then had dried out. Tar ballasts are pretty bullet-proof. They are just hot.

N

I use two 175w IceCap electronic ballasts. They were mounted on a wall beside (not under) the tank, using aluminum project boxes that house the ballasts and electrical connections. There is no heat sink other than this thin-walled aluminum box, and no fans are used.

One of them runs a little warmer than the other, but that's not saying much. The cooler running ballast doesn't generate enough heat to warm up my hand; I can barely tell when it's on. The warmer running ballast generates maybe about the same amount of heat on the side of the box, than a 4w night light would, if you held a night light near the side of the box for awhile.

It is my understanding that this is significantly cooler than core/coil ballasts run, but I have no way to prove that.

The main reason I chose electronic ballasts was the extra circuitry that helps to account for things like varying supply voltages (e.g. so the lights don't shut down when we turn on the clothes washer or something like that). Lights in my home tend to flicker when the larger appliances are turned on or off. As I didn't want line surges to cause my MH lamps to shut down, I chose these ballasts.

I have watched the lights during cycling of the washer, and I have yet to witness the lights getting shut down from a voltage drop after 5-odd months. I am very happy with the ballasts from that perspective.

These ballasts cost me about 2x as much as a core/coil PFO ballast would have. The payback period for the electronic ballasts was too long to be a factor in the decision - there's no way to know what I'll be doing with this tank in 5 to 10 years. I may decide I want 250w or 400w lights, or a bigger tank in that time.

If you're considering electronic ballasts because of efficiency, don't bother. Search the archives of this list to find our many discussions on this subject. Read the articles online having to do with calculating the payback period for purchasing electronic ballasts. Best case, if I ran my lights for 11 hours a day, it'd take 3 or so years to pay back that purchase. As it is, I run them about 5 hours a day, which is far too little to make an economic argument out of the efficiency purchase decision.

While the ballasts may help protect my lamps, they are not as hardy as core/coil ballasts. I have somehow managed to goof up one of my ballasts by shutting it on and off too quickly, requiring a trip to the shop for repair. While I expect this to be covered under warranty, I doubt it would have happened with core/coil ballasts.

Live and learn, eh?

N

There is not a single person on the planet who can answer this question with anything other than anecdotes and opinions.

And thank whatever God you believe in that you live in a country where it's OK to open your mouth and give your opinions and personal experience, and that some people go to the trouble of sharing theirs.

Bob Ashcraft

Why would you take offense to Mikes comment? It's completely true. Light is one of those things that 2 people can look at, and see 2 completely different things. What looks blue to you, may look green to me. What seems bright to me, may seem dim to you. There's nothing wrong with opinions and personal experiences, as long as they're expressed that way.

Mike Kirda

Why would you take offense to Mikes comment? It's completely true.

I was referring to the fact that there is zero scientific research that has been done with corals under differing MH lights. None. So, not one of us can say anything concrete one way or another. We can only relate our own experience and/or opinion. My point was to point this out, that none of us has 'the answer' the writer was looking for, nor can we, and why.

Anecdotes and opinions have their place in the hobby. Just a word to the wise: Recognize them for what they are. Do not take them as 'The Way'. A healthy dose of skepticism is a good thing.

N

It was an opinion of my opinion on lighting. I'm not God, and I don't know everything, and neither does anyone else. When one person wants to discount the opinion of another whilst at the same time saying that nobody can offer anything other than an opinion, that strikes me as kind of unnecessary. It's just his opinion, too.

I realize I said a mouthful in my original reply to the person asking the question. But in order to effectively make a point, or even to offer an opinion (which is what was asked for, remember?) sometimes one has to make statements that are not backed by conclusive scientific studies. To my knowledge there are few (if any) people on this list who could ever make a statement about anything in this hobby, if they had to also provide rigorous scientific proofs for every statement they made.

Personally, it is entirely reasonable to assume that corals thrive best under a light spectrum that most closely replicates the environment that the corals came from. I can't prove that, but intuitively it sure seems to be true.

Since the natural light spectrum changes with differing depths in water, it is also reasonable to state that different color temperature lamps used in this hobby can be used to create artificial environments that somewhat resemble the natural environments of our animals. I can't prove that either, but I think it's a reasonable statement.

It seems to me that all of our lighting systems are a compromise of some kind, which includes our own personal taste with regards to the color of the light we use to illuminate a tank. I am sure that our animals would prefer light that most closely replicates that environment they come from. Be that as it may, we usually want to keep them alive under a different spectrum of light than the one they come from.

Whether we choose to more closely replicate the animals normal environment, or choose to install light purely for aesthetic reasons, I believe, was the thrust of the original question. Of course, there are lots of opinions and no research. Nonetheless, it is still possible to offer an opinion or share some experience, even though proof is not to be found. That is far different than purposely trying to deceive someone, and far more useful than simply stating that nobody can answer the question with anything other than anecdotes and opinions.

Mike Kirda

Of course, there are lots of opinions and no research. Nonetheless, it is still possible to offer an opinion or share some experience, even though proof is not to be found. That is far different than purposely trying to deceive someone, and far more useful than simply stating that nobody can answer the question with anything other than anecdotes and opinions.

Let me try to make my point a little clearer.

Anecdote: A story about a subject that states your experience with the subject at a given time in a given set of parameters. i.e. My first sandbed system was a plenum-system. The most interesting thing about this system to me was the way it processed nitrates. The tank ran with nitrate levels way below what was detectable with a hobbyist test kit and would only register when used in a spectro-photometer. A normal 'high' reading was 0.001 ppm.

Opinion: Gives your subjective thoughts on the subject at hand. i.e. To me, the spectrum of the Iwasaki bulbs look very much like the light I see when snorkeling over a reef flat.

Scientific fact: Relating data taken from scientifically conducted experiments. i.e. 400W Iwasaki bulbs produce more PAR than any other 400W bulb tested.

When reading anything on this list, or on any board, one should always read the post and classify it according to the above. There are several people I have encountered who relate opinion as scientific fact. You have to learn to read and classify, apply the BS meter, then stop and think if the post:

1. Applies to you or your tank.
2. Is true.
3. Is interesting.
4. Considers further thinking.
5. Blatantly false.

etc., etc.

You want my opinion on the lighting upgrade? Simple: Upgrade to 2 x 250W Iwasaki bulbs. Add two VHO actinics if you don't care for the spectrum of the Iwasakis.

Where my opinion will differ is here: Based on the testing I have done with in-tank light levels, very few corals will find the intensity levels produced with this combination to be light-limiting. (This is where what appears to be opinion becomes more credible because it is based on testing of light levels.)

People should apply the same logic to all of my posts as well.