HQI lighting - differences in K values

[ChrisP]

OK, I know this is a really basic question, but comparing 150watt HQI lighting, aside from spectrum, is there a significant difference in light quality/intensity from one bulb to another?
Chris

[Ninong]

Yes.

[Ninong]

There are differences even between HQI lamps with the same wattage and the same advertised Kelvin rating. Different brands will almost always test differently. Not only that, but you can get drastically different results for the same lamp but with different ballasts.

[Ninong]

Read this article. Then if you still have questions, post them.

[Ninong]

Dr. Sanjay Joshi also has this handy reference site where you can compare various lamps by brand and Kelvin rating and wattage against other lamps and with various different ballasts. Check it out.

[zhenya]

There are differences even between HQI lamps with the same wattage and the same advertised Kelvin rating. Different brands will almost always test differently. Not only that, but you can get drastically different results for the same lamp but with different ballasts.

And, on top of what Ninong said already,they will test differently if you use different reflectors as well.

[ChrisP]

Thanks, Ninong! I looked at the articles and the guide, but, not being very technologically savvy, wasn't able to figure out how to compare the 3 bulbs I currently have (all double-ended - JBJ 14K, Hamilton 20K, and "Ebay generic" 14K) or my particular ballast. It's a magnetic JBJ "Gearbox." Aside from aesthetics, I'd like to know which of my 3 bulbs provides the most beneficial light for my corals.

I also wasn't able to answer the question - which manufacturer makes the best 150W, double-ended bulb, although I understand that this question doesn't have a simple answer.

Any guidance would be appreciated.

Thanks!

[Ninong]

Unfortunately, I couldn't find any of your lamps or your ballast listed in Sanjay's search base. That means that he hasn't tested them.

I decided to pull up the BLV 150w HQI DE lamp in both 20,000K and 10,000K and I used that with the PFO M81 ballast. I got PPFD numbers of 28 for the 20,000K and 67 for the 10,000K. That means that the 10,000K is 2-1/2 times as powerful (measured in PAR) as the 20,000K. This is as expected. (Those numbers are with a shield. Since a shield is absolutely required for HQI DE lamps, there is no reason to even consider the unshielded numbers.)

The reason I did that is because it's quite possible that BLV makes Hamilton's 150w 20,000K lamps. At least that's the way I believe it was several years ago. I have no idea if that's still good info or not. Maybe Hamilton has a different supplier now? The BLV factory outside Munich makes metal halide lamps under at least four or five different brand names. BLV is a wholly owned subsidiary of Ushio of Japan.

Anyway, in case you have no earthly idea what I'm talking about, PPFD = photosynthetic photon flux density. It's simply a unit of measurement of PAR (PAR = photosynthetically active radiation). The more PAR the better.

Dr. Sanjay Joshi takes his measurements with very expensive equipment from exactly the same distance. I believe each lamp is exactly 18" from the sensor. It's just a way of getting comparative data.

Your lamps are all sort of off-brand, if you know what I mean. In general, 14,000K and 20,000K lamps will be bluer than 10,000K lamps but they will also be a lot less intense. Something to think about.

[Ninong]

I also wasn't able to answer the question - which manufacturer makes the best 150W, double-ended bulb, although I understand that this question doesn't have a simple answer.

IMO, it's probably BLV/Ushio. That probably holds true for both 10,000K and 20,000K. Personally, I would never use the 20,000K by itself. I might use it mixed with 10,000K but never alone. It's too blue and not strong enough. That's to be expected with 20,000K lamps.

I don't think you can beat BLV/Ushio. They're all made at the same BLV plant just outside Munich but sold under different brand names. There are two or three other brands made there for other "manufacturers."

I used both BLV 250w 10,000K HQI DE lamps and AB 250w 10,000K HQI DE lamps. I preferred the BLV.

P.S. -- There are a lot of newer brands lately that I'm not familiar with. I have a tendency to give a lot of weight to reliability and reputation, too. Some of the newer bulbs from China in the past have been very disappointing.

[ChrisP]

What do you think about bulbs from this supplier: 150W 150 watt 14000K HQI DE Metal Halide Aquarium Bulb - eBay (item 260242298584 end time May-26-08 15:02:50 PDT)

Might it be worth risking $26?

[Ninong]

What do you think about bulbs from this supplier: 150W 150 watt 14000K HQI DE Metal Halide Aquarium Bulb - eBay (item 260242298584 end time May-26-08 15:02:50 PDT)

Might it be worth risking $26?

I wouldn't. It's too cheap. Could be junk from China. I would never buy anything on eBay unless it was a brand name that I was familiar with and could compare prices. You can't say if something is a deal or not if you don't know what it is in the first place.

How large is your tank? What exactly is your present lighting?

[ChrisP]

Thanks for the advice. My tank is a 24 gallon, top-removed Aquapod. The lighting is a 150W HQI Viper clip-on. The bulb sits about 4" above the water-line. and the tank is 15" deep. I glued a strip of 8 blue LED lights to each side of the upper top, pointing down, but the effect is barely noticeable when the HQI is on.

You mentioned the big PAR difference between 20K and 10K. What about in comparison with 14K? I think a 10K bulb would totally wash out any of the color on my zoos and ricordia (the main inhabitants).

Also - do you know anything about XM, Bluelife, and Phoenix brands?

[Ninong]

Also - do you know anything about XM, Bluelife, and Phoenix brands?

Sanjay tested the XM brand lamps. I've never heard of Phoenix or Bluelife. Are you sure it's Bluelife and not Blue Line? Blue Line is an in-house brand name used by Champion Lighting for lamps that are probably coming from Asia.

Anyway, here are the test results for the 150w XM HQI DE lamps using the same ballast as above for the BLV (M81) and shielded. XM 150w 10,000K HQI DE = 61 PPFD, XM 150w 15,000K HQI DE = 25 PPFD and XM 150w 20,000K HQI DE = 23 PPFD. As you can see, the numbers for the 10,000K and 20,000K XM are slightly lower than the numbers for the comparable BLV lamps.

P.S. -- Usually the 14,000K lamps are not nearly as intense as the 10,000K lamps. Usually they're just a tiny bit stronger than 20,000K lamps. And some 14,000K lamps are actually bluer than some 20,000K lamps.

[Ninong]

I decided to pull up the BLV 150w HQI DE lamp in both 20,000K and 10,000K and I used that with the PFO M81 ballast. I got PPFD numbers of 28 for the 20,000K and 67 for the 10,000K. That means that the 10,000K is 2-1/2 times as powerful (measured in PAR) as the 20,000K. This is as expected.

Here's the bottom line, based on your present fixture:

If you want to keep SPS or a clam or two in your tank, switch to the BLV 150w 10,000K HQI DE lamp.

If you're going to concentrate on Ricordea spp. and zoanthids and you like a bluish light, switch to the BLV 150w 20,000K HQI DE lamp. This is a VERY blue light and it has more PAR than most competitors' 14,000K, 15,000K and 20,000K lamps.

[ChrisP]

I've looked for BLV bulbs at Marine Deopt, Foster's & Smiths's, and Hellolights, but don't see them listed.

[ChrisP]

I'm sorry - looking back at the thread, I realize that BLV = Ushio. They have them at Marine Depot for $65.

[ChrisP]

Also - could a clam possibly be happy approx 8- 10" below the Ushio 20K?

[Ninong]

I've looked for BLV bulbs at Marine Deopt, Foster's & Smiths's, and Hellolights, but don't see them listed.

Remember what I said about BLV being owned by Ushio?

Marine Depot, Ushio 150w 10,000K HQI DE lamp.

Marine Depot, Ushio 150w 14,000K HQI DE lamp

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

Premium Aquatics, Ushio 150w 10,000K HQI DE lamp

Premium Aquatics, Ushio/BLV 150w 20,000K HQI DE lamp

Hellolights, Ushio 150w 10,000K HQI DE lamp

Hellolights, Ushio 150w 14,000K HQI DE lamp

Hellolights, Ushio 150w 20,000K HQI DE lamp

Item Code: 20-5000821
* Made in Germany by Ushio under the BLV label.
* A beautiful blue/white light!
* HQI - Double ended.
* Use this bulb with or without actinic supplementation!
* Use on ANSI M81 Ballast.

From that product description on Hellolights' website, it looks like they're telling you that your "Ushio" lamp is going to arrive with a "BLV label." It really makes no difference one way or the other. All of the Ushio and BLV metal halide lamps are identical and all of them are manufactured in BLV's plant just outside Munich. BLV was bought out years ago by Ushio of Tokyo. Both of the managing directors at the plant in Germany are Japanese.

[Ninong]

Also - could a clam possibly be happy approx 8- 10" below the Ushio 20K?

That's hard to say. I'm tempted to say "no." I know it would be OK 8-10" below the Ushio 150w 10,000K lamp. Your problem is that your tank is too small for anything other than crocea or maxima and those are the two most light-demanding tridacnids, especially crocea.

Both maxima and crocea should be placed on the live rock structure. Neither of these clams are naturally found on the sandbed. And all clams in nature face directly up. That provides them with the maximum amount of sunlight and it enters deep into their mantle when the sun is directly overhead. Therefore, clams should be placed facing straight up or, if you absolutely must tilt them a little towards the front viewing pane, don't overdo it. If you tilt a maxima or crocea clam, the inhalent siphon should be downslope from the exhalent siphon.

If I were you, I would avoid crocea because it's the most light-demanding and the most difficult to care for of the tridacnids. Tridacna maxima is my favorite clam (other than T. gigas, which requires a really big aquarium).

I don't know what to tell you about your chances with a maxima under a 150w 20,000K lamp. It might work, maybe. Daniel Knop, in his book "Giant Clams," recommends a minimum of 250w metal halides for all clams but some of them can thrive under other lighting if they are properly placed.

[Ninong]

Chris,

Just for kicks I decided to see if Sanjay had tested the Radium 150w 20,000K HQI DE lamp and he has: here.

Wow! PPFD = 47 for the Radium 20,000K. That's a lot better than the other 20,000K and 14,000K lamps.

That might be something to consider.