[Lucid]

I have read numerous times about if your lamps shift their spectrum to a more red, then algae blooms etc. Well, what would that kelvin range be considered? Like 6700K? Lower? What would be the best K ranges for a reef system?

Thanks fer input

[Ninong]

Originally Posted by Lucid

I have read numerous times about if your lamps shift their spectrum to a more red, then algae blooms etc.

I think what you probably read had to do with cyanobacteria, which is NOT algae. When lamps degrade, their spectral output often shifts more to the red into a range that is favorable to cyanobacteria.

Well, what would that kelvin range be considered? Like 6700K?

Unfortunately you have chosen a specific Kelvin rating -- 6700K -- that was picked out of thin air to describe certain compact fluorescent lamps that emit in the 450-460 nm range. These are actinic fluorescents that do not emit in the so-called "true" actinic range of 420 nm, often marketed as "true 03" actinics. I hope I'm not confusing you even more but there are, generally speaking, two different types of actinic, or blue, fluorescents: those that emit at 420 nm (called true actinics) and those that emit in a range near 450-460 nm. The people who manufacture compact fluorescents that emit in the latter range have chosen 6700K as the Kelvin rating for their lamps. Their lamps are NOt 6700K but that's the way they are marketed.

So when you say 6700K or lower, you are confusing the issue. You should have said 6500K or lower. However, to answer your question, 6500K is fine for a reef aquarium as far as most corals are concerned, especially SPS that are found in nature near the water's surface. The only problem with 6500K (or 6000K) is that it appears a little too yellowish to most hobbyists unless it is supplemented with lots of actinics. To make matters even more complicated, not all 6500K or 6000K lamps are the same. Some are more yellow in appearance than others. Which brings up another topic: you can't rely on Kelvin ratings at all when it comes to appearance because the various manufacturers lie about the true Kelvin ratings of their lamps. Many of them choose Kelvin ratings based on marketing without regard to the true Kelvin ratings of their products.

What would be the best K ranges for a reef system?

There is no one-size-fits-all answer to your question. A lot depends on what you prefer personally when it comes to the appearance of your tank. Some people prefer a more bluish appearance than others and are willing to trade PAR and higher growth rates for the blue appearance that they find attractive. You will have to research this topic a little more and decide for yourself what you like. Not what others like but what you like. Then you will have to decide if that's what you want or not.

If you're talking about T5 HO lamps, you can mix them to your heart's content and come up with just about any appearance. If you're talking about metal halides, you might decide that 10,000K lamps (for high growth) supplemented with actinic fluorescents give you a combination that you can live with both for optimal growth and a pleasing appearance. If you can tolerate 6500K Iwasaki halides and squeeze in enough actinics to "fix" their appearance, then you will have even more growth.

The bottom line is that no one can answer this question for you. You have to answer it yourself.



P.S. -- Some 14,000K halides are bluer than some 20,000K halides. Iwasaki markets a halide lamp as a 50,000K lamp. That's hilarious. It's not as blue as most 20,000K lamps. And all of the 20,000K lamps are not really 20,000K, they're simply "blue." They're too monochromatic to have a real Kelvin rating. That's why Radium says that their lamps are "blau" (German for blue) and not 20,000K. We call them 20,000K but Radium calls them "blau."

[Lucid]

Originally Posted by Ninong

Unfortunately you have chosen a specific Kelvin rating -- 6700K -- that was picked out of thin air to describe certain compact fluorescent lamps that emit in the 450-460 nm range. These are actinic fluorescents that do not emit in the so-called "true" actinic range of 420 nm, often marketed as "true 03" actinics.

SunPaq makes a supposedly 6700K daylight (CF), what I was getting at. My lamps are a mix of the 6700K/10000K, and of course mix of 460nm/420nm actinic.

I was wondering about algae (and cyano) growth under 6700 or less. My theory was if 6700 would not be good for reefs, then when it degrades, it would be really bad.

I will be looking into getting T5's in the near future and really wanted to know about Kelvin ratings etc, to not buy the wrong spectrum. Gotta love different manufacturers making their own 'ratings'. Kinda reminds me of many other products.

[Ninong]

Originally Posted by Lucid

My theory was if 6700 would not be good for reefs, then when it degrades, it would be really bad.

Your theory is wrong, so forget about it.

The Iwasaki 400w 6500K metal halide lamps are EXCELLENT for reefs, as are the Venture 1000w Sunmaster 6000K lamps.

I'm not going to get into a detailed explanation of spectral distribution but if you are interested, you can read some of Dr. Sanjay Joshi's articles. If you are interested in why cyanobacteria prefer certain wavelengths over others, you can do an advanced search using keyword "cyanobacteria" and user name "Ninong" as I have discussed this in excruciating detail more than once in the past.



P.S. -- As I mentioned in my previous post, some compact fluorescents that are blue (450/460 nm) are called "6700K." I have no idea why they are called that. It makes no sense whatsoever. The "true 03" designation that some manufacturers use to describe their 420 nm fluorescents is derived from the fact that the original actinic fluorescent lamps, manufactured by Philips, used "03" as part of their catalog item number.

If you look up Sanjay's spectral distribution chart for the Iwasaki 6500w metal halide lamps, you will find that they have more blue than many other lamps with higher advertised Kelvin ratings. In fact, if you compare the spectral distribution charts for a number of different brands of lamps that all claim to be the same Kelvin rating, you will find that their spectral distribution charts are quite dissimilar. The same holds true for PAR ratings. For example, not all metal halide lamps of the same wattage are equally good for your reef: the 175w Ushio 10,000K metal halide lamp has three times as much PAR as the 175w Venture 6000K lamp. Go figure.

[Ninong]

Originally Posted by Lucid

SunPaq makes a supposedly 6700K daylight (CF), what I was getting at. My lamps are a mix of the 6700K/10000K, and of course mix of 460nm/420nm actinic.

I will address the second part of this statement first. Exactly what brand of lamp do you have that is a mix of 460 and 420 nm? If so, that's a new one on me. In my experience, all of the Japanese square pin compact fluorescent lamps advertised as 6700K do not contain any 420 nm phosphors at all. (P.S. -- Looking at -- or photographing -- a 420 nm compact fluorescent, it will appear purple. The 450/460 nm lamps will appear blue. This holds true for T5's, too.)

I just looked up what you are talking about when you say "SunPaq's 6700K daylight (CF)." The 6700K they are talking about is a blue actinic lamp in the 450/460 nm range. Since it's a Japanese style square 4-pin compact fluorescent, rather than a German style 4-pin-in-a-row compact fluorescent, and since they are using the phony "6700K" designation, I will assume that it is the usual 450/460 nm lamp. The German lamps are usually 420 nm and advertised as "true 03."

So the phony designation of "6700K" is really confusing in this crappy marketing ploy because it confuses people. People may assume they really do mean an actual 6700K as meaning something close to actual daylight. They don't. This lamp is a dual compact fluorescent. One side is blue (which they like to call "6700K") and the other side is something they like to call 10,000K. It may or may not be an actual 10,000K but that's what they like to call it. They have decided to advertise these lamps as "SunPaq Daylight Power Compact Fluorescent 6700K Square Pin." Go figure.



P.S. -- Here's an interesting little story. Several years back, URI decided to change the Kelvin ratings advertised for their VHO lamps. Their daylight lamp, which was previously advertised as six thousand-something Kelvin was suddenly being advertised as 10,000K. There was absolutely no change in the lamp. It was the same excellent daylight lamp as before and nothing had changed except the Kelvin rating used for advertising it. Thankfully, they don't put a Kelvin rating on their actinic lamps at all and never have. Anyway, they now have a lamp advertised as 10,000K and another one advertised as 12,000K. All advertising. The designations have absolutely nothing to do with actual measurements. Their lamps are very nice VHO lamps and they are the same very nice VHO lamps as they were before under different Kelvin ratings.

Here's another interesting little story. There is no difference between the 55w and 65w compact fluorescents except the thickness of the leads. The lead-in wires on the newer 65w lamps are a little thicker than they were on the 55w lamps, allowing them to be run on 65w ballasts. One of the manufacturers actually rebranded some of their old inventory of 55w lamps as 65w and you could see where they tried unsucessfully to remove the old 55w designation. This provided an interesting topic for discussion on the boards at the time. People who received the old 55w lamps re-packaged as 65w sent them back for replacement.

[Lucid]

Originally Posted by Ninong

Exactly what brand of lamp do you have that is a mix of 460 and 420 nm? If so, that's a new one on me.

Aquarium Lighting: Current Compact Fluorescent Square Pin Bulbs

And the dual daylight lamp I mentioned is definitely yellow/white on both sides. They do have a 10,000K/460nm one though.

[Ninong]

Originally Posted by Lucid

Aquarium Lighting: Current Compact Fluorescent Square Pin Bulbs

Those lamps are not a mix of 420 and 460 nm. They're dual compact fluorescents: one side is 420 nm and the other side is 460 nm. When you said your lamps were "a mix of 460nm/420nm," I thought you meant that the lamp contained both 420 nm and 460 nm phosphors in the same tube. Anyway, they're dual actinic compact fluorescent lamps: one side is purple and the other side is blue.

And the dual daylight lamp I mentioned is definitely yellow/white on both sides. They do have a 10,000K/460nm one though.

Yes, I see that they are advertising what they call a "6700K daylight" compact fluorescent lamp. That could be confusing considering the fact that some manufacturers of compact fluorescent lamps have chosen to call their actinic lamps 6700K. I have also seen 7100K used to describe compact fluorescent actinic lamps. They really should have no Kelvin ratings assigned to them.

The manufacturer you are looking at has decided to use both 6700K and 10,000K to describe "daylight" lamps. They also offer a dual lamp that includes 10,000K on one side and 460 nm actinic on the other side. You can order daylight lamps that are 6700K or 10,000K or a combination. Maybe they should have chosen 6500K to avoid confusion when naming their yellowish daylight lamp?

P.S. -- Several years ago, Drs. Foster & Smith had a sale on 400w 10,000K metal halide lamps. The price was very good, too good. It turned out they were not 10,000K lamps. They were either 6000K or 6500K (I can't remember for sure right now). The manufacturer described them as "daylight" and the geniuses at Drs. Foster & Smith chose to call them 10,000K because according to their lighting "expert," daylight was 10,000K. I looked up the lamps in question on the manufacturer's website and found that they were not 10,000K. We complained to Drs. Foster & Smith and even emailed them a copy of the manufacturer's description. They dropped the sale for a couple of days and then reinstated it without the claim that they were 10,000K but with a $5.00 increase in the price!

[Ninong]

Dept. of Corrections:

I believe I was confused when I talked about 6700K being the Kelvin rating some Japanese manufacturers chose to market their actinic power compact lamps. I believe it was just 7100K. When the power compacts first came out, it was just Panasonic in Japan that was making them. Or at least they were the ones making them for the aquarium market and they chose 7100K to designate their actinic lamps, which were monochomatic in the 450-460 nm range. The ones being made in Germany were all of the 4-pin in a row design.

The German actinic power compacts were all advertised as "true 03" actinic because they were 420 nm.

I checked one of the vendor's websites and apparently there are some 4-pin square design power compacts that are advertised as "true 03," so I have no idea if they are 420 nm or not.

My main point is still valid and that is that these guys pull these Kelvin ratings out of thin air. There is no way in hell that a 450-460 nm lamp is 7100K.



P.S. -- Sorry about all the confusion between 6700K and 7100K. I'll blame it on my medication. Zhenya knows what I mean.

[Ninong]

Good example of nonsense in advertising:

Here we have a power compact lamp that is advertised as "dual actinic 03/7100K." The funny thing about that is that the "03" designation and the "7100K" designation are meaningless. Completely meaningless. The "03" part means absolutely nothing. It's simply part of the catalog number that Philips used for the first actinic fluorescent lamps, which were not power compacts. The "7100K" part is just a number pulled out of thin air. It does not in any way represent the true Kelvin rating of the lamps that emit in the 460 nm range. There is no correct Kelvin rating for a monochromatic 460 nm lamp.

The manufacturer's name is apparently "Current USA" and the product name is apparently "SunPaq PowerCompact Bulb" -- which is funny in itself since there is no way that a compact fluorescent lamp is a "bulb." A standard incandescent lamp might be described as a light bulb but the bulb part simply describes its shape. It's still a lamp. I can imagine calling any fluorescent lamp a fluorescent tube but never a bulb.

The vendor calls it "Current USA/Panasonic PowerCompact." That sort of sounds like Current USA and Panasonic are one and the same.

At least they have a nice little figure at the bottom showing the power compact lamp with one blue side marked 460 nm and one purple side marked 420 nm, which helps to clear up any confusion.