HQI lighting - differences in K values

[Ninong]

Marine Depot, Radium 150w 20,000K HQI DE lamp

Note: Radium does not advertise a 20,000K rating for any of their "20,000K" lamps. They simply call them "blau," German for "blue."

[ChrisP]

Just ordered the Radium 20K from Marine Depot, thanks to your excellent (and unbelievably timely!) advice.

One more question. I was thinking about fitting some eggcrate to the top of my tank to keep fish from jumping (when I get a couple). Do you feel that this will have a significant effect on the lighting strength. Also - might a clan be possible with the Radium bulb, placed on rockwork about 8" beneath the bulb?

[Ninong]

One more question. I was thinking about fitting some eggcrate to the top of my tank to keep fish from jumping (when I get a couple). Do you feel that this will have a significant effect on the lighting strength.

Yes, it will, especially with the light coming from a single metal halide source. It would make less difference with fluorescent tubes that extend across the full length of the tank because the light would be coming straight down evenly across the tank. With a single metal halide, even considering the reflector, a lot of the light is heading down at an angle.

I used eggcrate over my 120-gal tank but none of it was under the metal halide fixture. And the eggcrate over my tank was not resting on the tank itself. It was supported at a height equal to the height of the light fixture. My tank was jumper-proof because of my fairy wrasses. (See attached photos.)

Also - might a clan be possible with the Radium bulb, placed on rockwork about 8" beneath the bulb?

It might be possible. Again, don't attempt a crocea because they require the most light by far. Try a maxima and place it directly under the metal halide lamp.

[Ninong]

Another option that some hobbyists have employed for covering the top of their tanks is bird netting. I have seen that on top of some fairly large tanks. I think they sell it at home improvement stores, probably in the garden department. It's probably nylon and it's just a mesh (about 1/2" squares) with very fine "threads."

I'll see if I can find the pics that this one guy posted on another board. He made a frame for the bird netting so that he could simply lift up the entire frame for access to the tank. It looked like it probably had very little effect on the lighting.

Here is a photo of what that other guy did with bird netting.

[ChrisP]

Here's the "Bird Net Frame" top I've made. Chris

[ChrisP]

I put my Radium 150W, 20K DE bulb in today. WOW! Finally my corals are flourescing/"popping". It clearly provides actinic-like effects, yet, at least to the eye, seems far brighter than the 14K it replaced. I'm a very happy camper. Thanks so much for your advice, Ninong!

Now I have to figure out how to set the white balance on my camera. Photos of the tank look like blue dye was poured in.

[Ninong]

I put my Radium 150W, 20K DE bulb in today. WOW! Finally my corals are flourescing/"popping". It clearly provides actinic-like effects, yet, at least to the eye, seems far brighter than the 14K it replaced. I'm a very happy camper. Thanks so much for your advice, Ninong!

Thanks for posting the feedback on the difference between your new Radium 150w 20,000K HQI DE lamp and your previous 14,000K lamp. That's the sort of comment that helps others who are trying to decide what to get. This seems like a perfect choice for your particular tank (24-gal) and your particular fixture. Now you don't have to worry about how you might be able to add actinic lamps to supplement your fixture that holds only a single 150w DE lamp.

You seem to be pleased with your purchase even though it was more expensive than some of the other choices. One thing we have to always keep in mind and that is that we ourselves have to be pleased with the appearance of the tank. It doesn't matter how good a particular lamp is or how much PAR it puts out if we can't stand the look of the tank. In this instance, the Radium 20,000K in the 150w size seems to have more PAR than any of the 14,000K or 20,000K lamps tested by Sanjay. The only drawback seems to be that the price is a little higher.

Now I have to figure out how to set the white balance on my camera. Photos of the tank look like blue dye was poured in.

You should post that question in the Photo Lab forum.

[ChrisP]

The extra $30 I spent on the Radium bulb (as compared with Ushio, Phoenix, Hamilton, etc.) was forgotten immediately as soon as I saw the result of spending the extra money. Truly, it would have been worth double that.

[Tens]

does radium make a 250w 20k bulb? i just bought a new 250w MH pendant and heared good things about radium from other forums but i just cant seem to find a 250w 20k bulb

[charlie]

I happen to have one in my drawer, so the answer is yes.

[Ninong]

does radium make a 250w 20k bulb? i just bought a new 250w MH pendant and heared good things about radium from other forums but i just cant seem to find a 250w 20k bulb

Radium makes a 250w 20,000K lamp in the SE mogul base but not in the DE (double-end) style. They refer to their 20,000K lamps as "blau," not 20,000K. U.S. vendors will usually refer to them as 20,000K.

[Tens]

so they only make it in a SE bulb? well im on the hunt for a 20k DE BULB for my 250w pendant anyone have some good suggestions?

[Ninong]

Radium does not make a 20,000K DE lamp in the 250w size, just SE. Most of the 250w 20,000K HQI DE lamps put out about the same PAR, according to measurements taken by Dr. Sanjay Joshi. I have no experience with the Aqualine Buschke (AB) or Ushio/BLV 250w 20,000K HQI DE lamps but I have used their 10,000K DE lamps. Both brands have been around for a very long time and have a good reputation for quality products. I have no idea what the appearance of either of those lamps is in the 250w size. I have seen the BLV 150w 20,000K HQI DE lamp and it is very blue, if that's what you're looking for. I don't know if that will hold true for the 250w size in that brand or not. In the case of Radium, their 250w 20,000K mogul base lamp is bluer than their 400w 20,000K mogul base lamp.

Both AB and BLV produce about the same amount of PAR (meaning less than half the PAR produced by a 250w 10,000K HQI DE lamp of the same brand) in the 250w 20,000K HQI DE lamps. I would imagine that either of those would be a good choice, assuming your are intent on getting a 20,000K HQI DE lamp in the 250w size.

What lamp did your 250w pendant come with?

P.S. -- According to Sanjay's measurements, the Radium 150w 20,000K HQI DE lamp produces slightly more PAR than the 250w 20,000K HQI DE lamps from AB, BLV or XM. That's impressive.

[Tens]

my pendant comes w/ a 10k lamp and this is the 250w pendant i ordered SunDial HQI Pendant | Current What's Next i just want my corals to "pop" with color wich is why i want to go w/ a 20k lamp.

[Ninong]

I'm not exactly familiar with that particular brand of metal halide lamp. Current-USA is an importer. They don't actually manufacture anything. They import a lot of different equipment from various manufacturers in Asia and all of it is distributed under their house brand. I really have no clue who makes that fixture or the lamps.

In any case, you have a fixture with a 250w 10,000K HQI DE lamp and two 32w PC actinics. If you switch the 10,000K metal halide to a 20,000K metal halide you will give up half the PAR from the halide in exchange for a bluer coloration.

[Ajsim]

Hi,

I currently have a BLV (or Ushi ) 150 watt 14.000K bulb lighting my tank, together with 2 x 24 watt T5 (one actinic and one 10.000K). It is a nice bulb, but I am changing it into a BLV 150 watt 20.000K to make the colors more "pop". I have read this topic with serious interest, and I am curious about the color it will produce. I didn't know what brand the Radium is, but believe it is the same as Osram in the EU, does anyone know if that's correct? (i live in the netherlands).

If the results with the BLV are really disapointing, I might try the Radium too, that is, if I can get one.

[Ninong]

Hi Ajsim,




Radium is a German brand. Here is a German online vendor selling Radium 250w and 400w mogul base 20,000K lamps.

BLV, of course, is also a German brand but it is wholly owned by Ushio of Tokyo, Japan.

Osram GmbH of Germany is part of the giant conglomerate Siemens. I believe they go by the name Osram Sylvania in Canada and Sylvania in the U.S. I don't believe there is any affiliation with Radium but I really don't know for sure. I know that you can find metal halide lamps for sale in Germany under both brand names, Osram and Radium. Which probably doesn't prove anything because the BLV plant just outside Munich produces metal halide lamps branded as BLV and Ushio.

You will have to ask someone in The Netherlands if the Osram 150w 20,000K HQI DE lamp is the same lamp as the Radium 150w 20,000K HQI DE lamp. I found pictures of the Osram 150w 20,000K HQI DE lamp on German eBay but I was unable to find any of the Radium 150w 20,000K HQI DE lamp.

The 150w BLV 20,000K HQI DE lamp has a very blue appearance but, unfortunately, it's not much more than half the PAR of the 150w Radium 20,000K HQI DE lamp according to tests performed by Dr. Sanjay Joshi. According to Sanjay's measurements, the Radium 150w 20,000K HQI DE lamp produces slightly more PAR than the 250w 20,000K HQI DE lamps from AB, BLV or XM. That's impressive.

Those tests were performed on lamps sold in the U.S. under those brands. Since they're all made in Germany, I don't think it makes any difference where they're sold. I don't think the XM is made in Germany but the BLV, Radium, and AB are all made in Germany.

[Ajsim]

Hi,

Thanks for your reply. I didn't find a 150 watt radium as well on the internet, so i sent the vendor a email.

Too bad I read this thread after I orderded the BLV, but I am still curious about the color. Now knowing it produces far less PAR than the Radium, I think I will change the BLV as soon as I found a vendor where I can buy one. I have read a lot of positive reactions on the radium, although i also found a lot of positive reactions on the BLV. PAR was not mentioned, this is the first forum where I found this information. Seems to me that this is quite important ;;

Sylvania is also sold in the Netherlands, but I don't know if they have any connection with Osram.

[Ninong]

Sylvania is also sold in the Netherlands, but I don't know if they have any connection with Osram.

I found this explanation on Wikipedia when I googled Osram GmbH:

This international company, with its headquarters in Munich (Germany), employs more than 41,000 people throughout the world. World sales in the 2007 fiscal year totalled €4.7 billion. OSRAM supplies customers in about 150 countries and manufactures at 49 sites in 19 countries. They own the brand Sylvania for use in the United States, United States Territories, Canada and Mexico. The company's North American operation is Osram Sylvania, headquartered in Danvers, Massachusetts.

This is another one of those situations where a company markets the same products under different brand names in different countries. The other complication is that many of the brand names that we are used to seeing in our hobby are identical lamps made in the same factory under different labels. The BLV factory near Munich, for example, produces metal halide lamps for our hobby under four or five different brand names, only two of which are their own. The rest are sold by other vendors under their brands.

Over the past several years, the manufacture of a lot of aquarium hobby products (including metal halide lamps and ballasts) has shifted to China. The same factory may be under contract to produce products under more than one brand.

You have this happening to a certain extent with salt mixes, too. One of the large American salt mix manufacturers produces salt mixes under four or five different brands. Two of those brands are for their own use. The others are sold by other "manufacturers." Some of the companies selling 'their own' brand of salt don't actually make it themselves. The same is true with metal halide lamps.

I believe you will find that you get more 'pop' from your corals under Radium lamps compared to BLV. I have never personally used Radium lamps but that's what has been posted by a couple of members who have switched from BLV to Radium. I'm talking about 20,000K to 20,000K. I used both AB and BLV in the 250w 10,000K lamps and I preferred the BLV over the AB because of the coloration even though the AB has slightly higher PAR. The BLV seemed to produce a whiter white. The AB's coloration may have been closer to sunlight in appearance but I liked the BLV better.

It's all just a matter of personal preference when it comes to the appearance of the various lamps to our eyes but PAR is the most important consideration as far as the corals are concerned, assuming the spectral distribution is appropriate. In other words, you can have all the PAR in the world but if the lamp is one designed for horticulture, it won't be appropriate for our needs.

P.S. -- Dr. Sanjay Joshi (Ph.D. in mechanical engineering) has tested hundreds of metal halide lamps with various ballasts. Those test results can be searched. All lamps are tested from the same distance, 18" (46cm). Many of the lamps were tested with and without a glass UV shield (the sort of shield that you must use with DE lamps). My Aqua-Medic fixture used a 3/16" tempered glass shield.

[Ajsim]

Sylvania produces 2 bulbs suitable for seawater, the AquaArc (10.000K) and the CoralArc. They don't say what kelvin rate the bulb is, just this:

Very high colour temperature (bluish light)
Very high colour stability over the whole lamp life
Enhanced colour rendition

and also:

For use over sea water aquaria
Provides the specific spectrum (400 - 480 nm) necessary to achieve the blue chlorophyll absorption for zooxanthellae symbioses to develop

Maybe this is the same bulb as the Radium? Tomorrow if will try to find out.