Disappointing PAR from 250MH.

[Builderguy]

This is about 1/2 of what I was looking for: Water Surface 0" 240-270ppfd
6-8" 140-170
12" 100
18" 75
Bottom 24" 60

Hamilton M58 ballast with added ignitor to fire HQI.
Cheap "marine color" 20k.

I have heard these opaque sensor par meters read about 17% low.

The spread is really even, so I'm happy with that. Did I over do it and thin out the light too much? I expected a hotspot closer to 500, 8" below the reflector. Is this what I should expect from a 20k bulb? Are these bulbs THAT lame? Should I toss in a 10k? Is the m58 under firing the bulb? My understanding is that the ignitor is the only difference.

If this doesn't seem far off for a 250 20k I might go 400. Whatcha think?

 

[PPBlimpy]

It’s been a long time since I ran halides but I am going to guess the reflector isn’t helping much and a 20k bulb will kill par values compared to a 12-14k

Also how many hours does the bulb have on it? I remember my old 250w 12k breaking in over the first 10-15 hrs(this was 20years ago)

 

[minus9]

Those cheap Chinese bulbs are all over the place in regards to consistency. I would look for a Hamilton 20k or 14k bulb and add some Quanta Helix meso blue bars to fill in the "pop" spectrum. Also, you want the M80 ballast and not the M58. They are making Radiums agian Aqua Bright
Regardless, you have the wrong ballast.

 

[BeanAnimal]

PAR is not the right metric to determine how well a light is going to grow coral. And to that end, what is "250" If it is 20% to 40% different depending on meter, user error, etc.?

The lamps are either going to grow coral to your liking or not. What does a PAR meter have to do with that?

 

[Builderguy]

It’s been a long time since I ran halides but I am going to guess the reflector isn’t helping much and a 20k bulb will kill par values compared to a 12-14k

Also how many hours does the bulb have on it? I remember my old 250w 12k breaking in over the first 10-15 hrs(this was 20years ago)

Its 2 hours old. I figured the difference would be... I mean less than what I'm seeing vs expected.

Those cheap Chinese bulbs are all over the place in regards to consistency. I would look for a Hamilton 20k or 14k bulb and add some Quanta Helix meso blue bars to fill in the "pop" spectrum. Also, you want the M80 ballast and not the M58. They are making Radiums agian Aqua Bright
Regardless, you have the wrong ballast.

Problem is I want 14k if I'm going to shell out 90 bux for a bulb. I'm using Lomini Asta 120's for pop. You can see the opening at the corner of the hood for one, and there's another spot opposite. I do like the drama of a point source LED over bars and panels.

I just found a label for an m80 ballast. Pix attached. The m80 runs 50 volts lower, with a higher SCC. I used to run... Geeze was it an icecap?... Just like this. Back then I wasn't burdened with excess information so who knows. Maybe it had the same problem, maybe it didn't.

PAR is not the right metric to determine how well a light is going to grow coral. And to that end, what is "250" If it is 20% to 40% different depending on meter, user error, etc.?

The lamps are either going to grow coral to your liking or not. What does a PAR meter have to do with that?

True that. With differences in LEDs these days it's the closest thing to measure apples to oranges, I suppose. A couple years ago I had a cyphastrea and an acro near by each other. In such a way that the cyphastrea got some shade. Well I couldn't figure out how one would do well or the other would, they never looked good simultaneously.

So I get this par meter and measure around after messing with settings a few times, turns out when I was vacuuming the sand bed I was repositioning the light differently and it made a HUGE difference in what each coral saw, ppfd-wise. So I raised the light and turned it up, problem solved they both looked great happily ever after.

All that's to say, since I've poked around my tank and under the light I have noticed that with this lunar lander of a reflector the meter will read 120-150 facing this way or that way, it doesn't matter.

In the tank my Oregon tort is getting 275 if I face the light but only 80 if I face a way, but just a little, 45° at most.

To your point BA, it's hard to quantify that kind of quality of light. I very well could have double the photons reaching the same point in space in such a way the meter can't measure.



Right now I'm thinking my course of action is to install the hood, then source a probe start bulb in the 10k range to upgrade in a month. And do some digging on that OCV, freshen up on my ballast knowledge.

5701 is my ballast, 5880 is online source for an m80 label.

 

[ChrisfromBrick]

im betting that PAR meter is off. MH is so powerful, though it does give off more energy in the form of heat than other lights.

 

[JBNY]

Here is where the bulb make a huge difference in PAR. There is a reason brands like Ushio, Radium, aquaconnect etc were used so often, it is not easy to get decent par with with any MH lamp. The more blue you go that harder it is to get decent PAR. That is why you see so many 10K bulks, a few 14K bulbs, and only one or two 20K bulbs. A long time ago I measured a ton of lamps and ballasts, https://reefkeeping.com/issues/2007-04/jb/index.php/ there is a huge difference in PAR.

 

[BeanAnimal]

im betting that PAR meter is off. MH is so powerful, though it does give off more energy in the form of heat than other lights.

Actually they are very similar in terms of turning electrical energy into light. They waste similar energy to heat, but differ in the way that heat is shed.

 

[BeanAnimal]

Here is where the bulb make a huge difference in PAR. There is a reason brands like Ushio, Radium, aquaconnect etc were used so often, it is not easy to get decent par with with any MH lamp. The more blue you go that harder it is to get decent PAR. That is why you see so many 10K bulks, a few 14K bulbs, and only one or two 20K bulbs. A long time ago I measured a ton of lamps and ballasts, https://reefkeeping.com/issues/2007-04/jb/index.php/ there is a huge difference in PAR.

And “higher PAR” does not mean “better”. It is a very poor metric for trying to compare lamps of different spectra

 

[rtparty]

An M58 ballast is probe start whereas an M80 is pulse start. Which one you use is dependent on the bulb you are running. The ballast likely isn’t the issue here.

The sub optimal reflector and cheap bulb are the issue. Buy 10 cheap bulbs and get 10 different results.

Radiums are not the 20k we are used to today. They are much more 14k. Yes, they are $90 each. However, on an M80 ballast they will last 2, 3, maybe even 4 years.

The 2 over mine in a Giesemann Spectra blanket the tank in 300-400 PAR

 

[JBNY]

And “higher PAR” does not mean “better”. It is a very poor metric for trying to compare lamps of different spectra

But what to use? PAR is supposed to measure everything equally from 400nm to 700nm, breaking it out by spectrum band would be cool, but I don't know how we could do that easily.

 

[BeanAnimal]

But what to use? PAR is supposed to measure everything equally from 400nm to 700nm, breaking it out by spectrum band would be cool, but I don't know how we could do that easily.

We don't even know which of those bands are actually important, let alone how much energy should be in those important bands. It is kind of like rating the sound quality of a speaker by its loudness, the number is measurable but really means very little for the purpose.

 

[oreo54]

im betting that PAR meter is off. MH is so powerful, though it does give off more energy in the form of heat than other lights.

ZEISS Microscopy Online Campus | Metal Halide Lamps

Metal halide illumination sources are rapidly emerging as a serious challenger to the application of mercury and xenon arc lamps for investigations in fluorescence microscopy.

zeiss-campus.magnet.fsu.edu

 

[ChrisfromBrick]

ZEISS Microscopy Online Campus | Metal Halide Lamps

Metal halide illumination sources are rapidly emerging as a serious challenger to the application of mercury and xenon arc lamps for investigations in fluorescence microscopy.

zeiss-campus.magnet.fsu.edu

so what you’re saying is, while they do get hot, you aren’t sacrificing the right light for heat?

 

[oreo54]

ZEISS Microscopy Online Campus | Metal Halide Lamps

Metal halide illumination sources are rapidly emerging as a serious challenger to the application of mercury and xenon arc lamps for investigations in fluorescence microscopy.

zeiss-campus.magnet.fsu.edu

What I'm showing is leds don't have that IR emissions which are added to the energy to wavelength equation.
Zeiss 20% , Ushio 14000K everything above 850 for the most part.
IF mh IR is "waste" or not is an open question. As is UV.

Our AI overloads take.

Metal Halide Energy Distribution

• High Heat, Low Efficiency: Metal halide (MH) lamps are High-Intensity Discharge (HID) lights that waste a large portion of energy as unwanted heat (infrared radiation) and UV light, not just visible light.
• Energy Breakdown: Much of the energy is lost through the arc, electrodes, and hot envelope, meaning only a fraction becomes useful light, with estimates suggesting large percentages become heat.
• Operating Conditions: They operate at very high temperatures (around 2,000°F inside the arc tube) and require several minutes to warm up to full brightness.

LED Energy Distribution

• High Light, Low Heat: LEDs convert a much higher percentage of electricity into visible light, drastically reducing wasted heat compared to MH.
• Heat Generation: While efficient, LEDs still convert a portion (around 15-25% or sometimes up to 55% in older/specific types) of power into heat, which must be drawn away via heat sinks and heat sinks.
• Instant & Cool: They provide instant brightness, no warm-up, and run much cooler, reducing strain on air conditioning and eliminating UV/IR output.

KEEP in mind these are generalizations.... LED and MH "efficiencies" can vary by brand/type/ect...and does not include system efficiencies.
Drivers/ power supplies/ballasts

 

[ChrisfromBrick]

I need to read more about lightning. This stuff bends my noodle

 

[Riptideacro]

You mentioned you’re going to use Lomini Asta 120's, I did this exact combo 250w marine 20k Amazon bulb with the 120’s as that extra “pop” and the Lomini Asta 120's are a fire hazard. One of them started smoking and wouldn’t stay on.. the power pack gets so hot and would melt.. I really do not recommend them. I switched to t5s as supplemental lighting, I also went with a radium bulb 20k and it’s way better light then the amazon bulb. If you give the bulb more juice it is way less blue. Which I prefer.

 

[djf91]

Here is where the bulb make a huge difference in PAR. There is a reason brands like Ushio, Radium, aquaconnect etc were used so often, it is not easy to get decent par with with any MH lamp. The more blue you go that harder it is to get decent PAR. That is why you see so many 10K bulks, a few 14K bulbs, and only one or two 20K bulbs. A long time ago I measured a ton of lamps and ballasts, https://reefkeeping.com/issues/2007-04/jb/index.php/ there is a huge difference in PAR.

JBNY! Now that’s an old name I haven’t seen in awhile. Always loved your tank of the months.

 

[Builderguy]

... and the Lomini Asta 120's are a fire hazard. One of them started smoking and wouldn’t stay on.. the power pack gets so hot and would melt.. I

I did read reviews of that, I'm using a UL listed transformer meant for home LED permanent install. I needed one box anyways to run them on a single TC-421. One is 3, the other is 4 years old.


To update the original topic, I picked up an Aquabright 10k. YEESH. With blues on I think it's around 10k. But the par numbers I'm seeing are more akin to what I expected with a nice 350-450 peak under the bulb and a spread of around 200 throughout the tank. The hood might not be considered efficient.... Or pretty... But it accomplished my goal of even lighting in a 14" tall package. Because my overflow IS the rockwork, I had to get around the faux pas of putting rocks higher than halfway up the tank.

Anyhow, I believe the issue was the current limiting nature of the coils. My old ballast was an hqi that I wired the the starter OUT of, apparently it does not work the other way around.

Kinda fun taking pictures without a filter though.

 

[PPBlimpy]

I did read reviews of that, I'm using a UL listed transformer meant for home LED permanent install. I needed one box anyways to run them on a single TC-421. One is 3, the other is 4 years old.


To update the original topic, I picked up an Aquabright 10k. YEESH. With blues on I think it's around 10k. But the par numbers I'm seeing are more akin to what I expected with a nice 350-450 peak under the bulb and a spread of around 200 throughout the tank. The hood might not be considered efficient.... Or pretty... But it accomplished my goal of even lighting in a 14" tall package. Because my overflow IS the rockwork, I had to get around the faux pas of putting rocks higher than halfway up the tank.

Anyhow, I believe the issue was the current limiting nature of the coils. My old ballast was an hqi that I wired the the starter OUT of, apparently it does not work the other way around.

Kinda fun taking pictures without a filter though.

Looks good to me!