Stupid Question - what is T5 / MH lighting?

[EeyoreIsMySpiritAnimal]

I wouldn't worry about it, orpheks spread them pretty good. The telltale sign of the old narrow LED is the "discoball" effect you seem at the bottom.. the orphek website, for what its worth, also mentioned the spectrum as one of their strengths/selling points.

I really like the Icon, its fits pretty well on top of my jbj aio65. Just 1 gives really good spread with plenty of par and the right spectrums, and provides that clean look without the messy 5-6 wires that comes from having 5-6 different lights

Is that a stock hanging kit or something you built?

 

[gbru316]

Actually Orphek found my post awhile back and provided me with their PAR charts. Pretty legit. It was however a little difficult to comprehend..

I run my lights 12" over the water. I believe the 0/15/30 cm is the distance front to back from the light, and then again from left to right. So with a 75g, it's 18" front to back so I would be looking at the top chart, and my numbers would be between the 30/15 cm marks.

Not quite.

Each chart represents a distance between the light and the meter, in air. The top chart is at a distance of 15 inches, the middle chart is at a distance of about 6.5", and the bottom chart is about 22"

Look at the chart like a top down view of the light. The rows and columns represent physical locations around that plane. ie, 0,0 on a chart is centered directly under the light. Using the top chart as an example, at a distance of 30 cm behind, and 30 cm to the left of the center of the light, at a distance of 15" from the light, PAR was measured at 11.

It's important to note that these are air measurements. Underwater PAR will be reduced.

 

[rtparty]

I don't think people have that intention. I think they have the expectation that they need that level of complexity, when in reality, they probably don't. I personally don't think anyone NEEDS the best equipment, or the best spectral coverage or whatever. A lot of this hobby focuses on perceived value, theory and tank appearance rather than focusing on the actual health of the tank and proven equipment, methods which isn't as interesting.

No doubt. We all like shiny new toys

 

[Dkmoo]

Is that a stock hanging kit or something you built?

The wire kit came with the light but since the family room has slanted drywall ceiling I didn't trust my own hanging/anchoring skills to be able to safely support the weight. So I built my own brace/rack with 8020 aluminum extrusion bars thats bolted to the cabinet - very similar to how Reefdude did his rack in that youtubr video. He did one long bar bc his tank is peninsula, I did 2 short bars.

The wires you see is just secondary backup to spread the weight even more as an extra precaution

 

[Crustaceon]

No doubt. We all like shiny new toys

And that's understandable for us humans. Our corals on the otherhand are wondering why there's a thunderstorm indoors and why the sun is turning into a blacklight and then sun and then off and then more intensity and then less every few days.

 

[Kathy Floyd]

The "character" of the spectrum in LED light is different from T5/MH. Not all "par" are created equal.

T5 and MH offer not only broad spectrum, but "fuller" spectrum, in their lights than LED. "Fuller" meaning it covers every frequency of light within the spectrum it offers. Even say you get a "blue" T5, the blue that comes out of it covers all the frequency within that blue spectrum.

LED, on the other hand (at least the old school LEDs), emits at a very specific frequency. Even the "broad-spectrum" lights are more just a mix of individually specific frequency lights in red, blue. Green. Purple, etc. The LED photons, are more like tiny lasers

Think of it as watering your plant, even if you water the same volume of water (PAR), T5/MH is like a wide gentle spray, LED is like a thin strand of high pressure nozzle

People use hybrid setups for aesthetic. Usually T5/MH provides the general "fill light" for coral growth. LED is then added to provide those specific spectrum that the coral florescent proteins react the most actively against (usually blue/violet) to give that crazy "pop" in color for the tank

Having said ALL of that, the new generation of LEDs have come a long way from those early "tiny lasers". With the aid of built-in diffusers and other new LED techs, these newer lights are now very comparable to the old T5/MH in terms of broad/full spectrum while maintaining that "pop". Its also more energy efficient that t5/mh.

I used to run hybrid, now I'm 100% LED. I run an orphek icon.

I love this explanation.

 

[ilikefish69]

I love this explanation.

The watering of the plant is by far the best way I have seen this explained. I used to teach middle school math. To take a difficult topic and put it in terms that anyone can understand is not easy. I mean I even "did my research" before coming here. Of course, my research always quickly goes out the door when I have reefing experts quick to share their knowledge.

 

[ilikefish69]

Not quite.

Each chart represents a distance between the light and the meter, in air. The top chart is at a distance of 15 inches, the middle chart is at a distance of about 6.5", and the bottom chart is about 22"

Look at the chart like a top down view of the light. The rows and columns represent physical locations around that plane. ie, 0,0 on a chart is centered directly under the light. Using the top chart as an example, at a distance of 30 cm behind, and 30 cm to the left of the center of the light, at a distance of 15" from the light, PAR was measured at 11.

It's important to note that these are air measurements. Underwater PAR will be reduced.

That does make more sense. Is there a constant ratio of the underwater PAR reduction that I could possibly apply to these values?

And while I've got you on the line (lol) would adding a second, and then third light increase the PAR readings at a constant rate. For example, if one light produced 11 PAR, would two produce 22 and three produce 33? Or is it less, or more? I could justify all three in my head, but obviously only one would be the case.

 

[gbru316]

That does make more sense. Is there a constant ratio of the underwater PAR reduction that I could possibly apply to these values?

And while I've got you on the line (lol) would adding a second, and then third light increase the PAR readings at a constant rate. For example, if one light produced 11 PAR, would two produce 22 and three produce 33? Or is it less, or more? I could justify all three in my head, but obviously only one would be the case.

1. No. The reduction is going to depend on a few different things: angle of incidence, turbidity, and type of light, for instance.

2. Depends on the type of light. For a point light source (LED pendants/fixtures -- not bars, metal halide), no. You're always going to have "hot" spots directly under each fixture, and the light will taper off between the fixtures. But that doesn't mean that multiple fixtures should be avoided -- they're absolutely necessary to prevent this "spotlighting" effect. Ideally, you'd have enough where you wouldn't visually notice a reduction in light between the lights -- but it'll still exist to some extent.

This is totally avoided with T5 (and LED bars) since they're area lights, not point lights. For all intents and purposes, adding another T5 bulb (or LED strip) adjacent to an existing T5 bulb/strip will increase PAR uniformly across the tank.

 

[Dkmoo]

That does make more sense. Is there a constant ratio of the underwater PAR reduction that I could possibly apply to these values?

And while I've got you on the line (lol) would adding a second, and then third light increase the PAR readings at a constant rate. For example, if one light produced 11 PAR, would two produce 22 and three produce 33? Or is it less, or more? I could justify all three in my head, but obviously only one would be the case.

I'd suggest a par meter (whats another 200$ on top of this expensive hobby amirite?)

In vacuum, physics tells us that luminosity is inversely square related to distance, so 2x distance is 4x dimmer, 3x distance is 9x dimmer. However, in our tanks that formula goes out of the window because of the internal reflection of light bouncing off the inside of the glass pane back into the tank. So, depending on the angle of the internal reflection, the distance from the light, the height above water, this ratio can vary a lot. In all cases tho it will dim a lot slower than the inverse square formula because of the internal reflection.

 

[alton]

When I first got into the hobby on small tanks we used three cool white lamps and a Philips 03 lamp. For larger tanks VHO lamps and metal halide. Today Metal Halide is still being used by people with tanks over 300 gallons with LEDS to supplement. My oldest LED fixture is 10+ years old BML and still has plenty of PAR. The first LEDs where junk and how many said a PAR meter could not read them correctly. Now LED fixtures last a long time and do well when measured on PAR meters and coral. T5's where nice, lamps just didn't last for me with my MH lamps lasting 16 to 24 months on average.

 

[ilikefish69]

I'd suggest a par meter (whats another 200$ on top of this expensive hobby amirite?)

In vacuum, physics tells us that luminosity is inversely square related to distance, so 2x distance is 4x dimmer, 3x distance is 9x dimmer. However, in our tanks that formula goes out of the window because of the internal reflection of light bouncing off the inside of the glass pane back into the tank. So, depending on the angle of the internal reflection, the distance from the light, the height above water, this ratio can vary a lot. In all cases tho it will dim a lot slower than the inverse square formula because of the internal reflection.

Well I got about 80% of the way through this and my eyes got crossed. But it sounds like no there is no constant ratio. Why can't anything in life ever be easy? lol. Also, I've been hinting to LFS that they should just let me borrow their PAR meter and bring it back to them an hour later. I think I am making some progress...

 

[gbru316]

Well I got about 80% of the way through this and my eyes got crossed. But it sounds like no there is no constant ratio. Why can't anything in life ever be easy? lol. Also, I've been hinting to LFS that they should just let me borrow their PAR meter and bring it back to them an hour later. I think I am making some progress...

No need to buy a dedicated PAR meter. The Photone app measures PAR close enough for our purposes:

Android: https://play.google.com/store/apps/details?id=io.lightray.photone&hl=en_US&gl=US

iPhone: https://apps.apple.com/us/app/photone-grow-light-meter/id1450079523