When is 14k not 14k?

So I have been using AquaMaxx 150w HQI 14K bulbs for a couple cycles now, about 2 years, and they look good and I get good response from my corals. I let the last batch go too long between replacement, and ordered some Ushio 14k bulbs since the LFS didn't have any 150 HQI's in 14k. I knew to expect SOME difference between major manufacturers, but not this much.....

The AquaMaxx were quite blue, not 20k blue, but enough that people would commen on the color... the Ushios are much MUCH warmer, pretty much yellow...closer to what I've experienced with the 10k bulbs at the LFS...

I know some bulbs experience a burn-in time, but with the AquaMaxx bulbs I never noticed one... or if there was one it was very subtle, I do not see these bulbs turning blue any time soon....


So I guess my question is, what's up? Why is one company's 14k bulb yellow, and another blue? Shouldn't 14k = 14k anywhere in the jurisdiction of physics?

Also, should I worry about the abrupt change in spectrum affecting my corals? They're already pissed that I left them under bad bulbs for 2 or 3 months longer than I should have...


Thanks!

-Doug

 

IMO..first ..no, they are not the same brand to brand...many post and links to par and spectrum..
second..yes, abrupt spectrum/par change does have an effect on corals...but in this instance...it does not seem relative...I don't believe its that broad to be concerned with acclimation....but again jmo. I think your cool...as so are they.

 

BTW...those back boobs on your avatar...I think I just thew up in my mouth...thanx. : / lol

 

The fact is that there are very few MH bulbs that will perform to the true kelvin temperature that they are marketing. If you can see any hint of blue, it is most likely over 30K. The Ushio is a true 14K bulb.

 

I just reviewed the test data. The Ushio tested out at 11K

Sanjay's meter reads up to 40k. Here is a list of some popular 10 - 14K that tested out at more than 40K

Phoenix Hexarc 14K (has nearly the PAR of 10K bulbs)
Aquaconnect 14K
EVC 14K
Icecap 10K
Hamilton 14K

Next to the Phoenix, my next favorite bulb is the Iwasaki 15K and even it tested out at 38K.

 

Thanks for the ton of info all!

So I get that PAR is variable, since it's composed of a broad range of the visible and near-visible spectrum, and component output in any given sample range will vary, so long as the total PAR is equal to an advertised amount....

But K is, if my college light and optics physics classes serve me correctly, an objective reference for observable color related to the thermal emission of a heated black body...
(edit: correction, it's not related to observation, it's absolute... CCT is the observable color, but the point remains mostly intact)

If 2 companies offer bulbs that are 14,000K in color there should be only a minimal variation between them.... maybe falling in a range between 13,500 and 14,500.

What you're saying is that it's common and accepted that the variation is in excess of 300% ???

Man, I call shenanigans. These bulb manufacturers are plenty capable of delivering a product in a given range and do so all the time for imaging, technical, and architectural lighting... often cheaper than similar wattage/output bulbs for the aquarium trade where lives depend on them... I can only imagine what the result would be if a major studio bought a 5700K bulb and got a 6300K bulb, or a lab needed 4800K and got 5200K marked 4800K .... lawsuits, or at the very least shunning of a company within an industry.


Any links where I can find anyone else with info? I'll check out Sanjays website later... but this is serious stuff. WHY is this accepted at all?


also, back boobs ftw! it's from peopleofwalmart.com

 

I can offer no comment on the various colour temperature variations between manufacturers having only used MH lamps for less than 9 months thus far

I can comment on the fact that changing lamps, even lamps with a so called identical colour temperature, of the same brand can have an effect on your corals

so I would suggest reducing the lighting period should you see obvious indicators of stress such as LPS corals closing up earlier than was normal under the previous lamps

LPS corals are great indicators of potential light saturation issues which can and do lead to bleaching as they have the ability to reduce their mass in order to offer less surface area to the light

Steve

 

You are correct in your understanding of Kelvin temp. Keep in mind that ther is no 20K in architectural bulbs. They are simply called blue. In our hobby, we simply relabeled them with the generic term 20K. This is how we got the Radium and Ushio 20K bulbs. The Phoenix 14K is really called the Phoenix Hexarc blue.

There is no standardization nor oversight in the marine aquarium industry. Basically you can call it's color whatever you want. It's no different in LED either. In our industry a blue MH bulb is a 20K. In actuallity it is probably 80K but we really don't call them anything more than 20K. Years ago, Iwasaki cam out with a 150 watt 50K. Basically most people steered away frm it thinking it was twice as blue as a 20K. In reality, it was probably close to being a true 50K which in our industry would fall in the 12K range. It was white with a slight hint of purple.

In this industry you must remember that most of the lighting companies do not make their light sources. They haqvce others OEM the lights for them. They are not lighting engineers. They are mostly marketing guys who follow in suit what their competing companies are doing. You must also remember that our industry is very small. Yes we are passionate and very active and vocal but it is a very small. Remember we are not the marine aquarium hobby. We are a subculture of that which is referred to as reefkeepers. There just isn't enough of us to have to worry about regulation. We are all vocal enough to share our experiences on forums such as 3reef. It you are ever unsure of a product, you can always post the question on the web and someone else will most likely have an opinion on it. That is what makes 3reef great!

 

Fantastic info, K+

 

So it's been a week and the bulbs have shifted towards closer to what I recall the previous lights looking like. They're still not as blue, but there's a blue tint to them that puts them in the right range.... the first few days they were like jaundiced yellow, now they're closer to what the LFS sells as a 10k bulb, but I can see the color returning to the tank.

The other thing it has highlighted is how yellow my water is.... I suspect mass algae spores, since i am in the middle of a GHA outbreak, with a side of bubble algae and a garnish of escaped chaeto in the DT.


still a lot of work to do getting this tank back in line