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Is there a cheap way of figuring out high light?

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Hello folks,

Planning in the next few months to do my first high tech tank build. Just because I am a gluten for punishment I am also trying to make my lighting system meet a specific aesthetic quality. Specifically I am going to have my lights be suspended about 2 feet above the tank (maybe a little less, will play with it once I get it setup). My tank will be a 120 gallon, 48" long and 24" deep. So it will be around 4 feet from light source to substrate.

My plan right now involves using screw in LED bulbs (Not sure how many, 3-6?) to get what I need. Also not sure on the wattage I will use since that will depend on how successful I am at getting the light to the substrate. Which brings us to the point of this post.

Is there a cheap method of determining if I am successful in my setup? When making this system I need to know if I need 3 lights or 6 lights. If I should be using 20watt LED bulbs or 150 watt COB flood lights. etc. etc.

I have been reading about PAR and PPF and YPF, etc. The only thing I have walked away with so far is that figuring out what people call par but should probably be called ppfd is an expensive proposition of around 500 dollars if you want to be sure you are getting it right.

Meanwhile I am wondering if I can just buy a luxmeter and some gel filters so that I can "undo" the yellow-green light weighting that those systems rely on to measure brightness.

Is there a way out of this rabbit hole that will cost less then my lights? Any guidance would be greatly appreciated.
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My plan right now involves using screw in LED bulbs (Not sure how many, 3-6?) to get what I need. Also not sure on the wattage I will use since that will depend on how successful I am at getting the light to the substrate. Which brings us to the point of this post.

Is there a cheap method of determining if I am successful in my setup? When making this system I need to know if I need 3 lights or 6 lights. If I should be using 20watt LED bulbs or 150 watt COB flood lights. etc. etc.

I have been reading about PAR and PPF and YPF, etc. The only thing I have walked away with so far is that figuring out what people call par but should probably be called ppfd is an expensive proposition of around 500 dollars if you want to be sure you are getting it right.
Have you seen any high tech tanks that are successful with 20w screw in LED bulbs? Or with 150W COB flood lights?

If you have, I would get in touch with those folks and find out more about their set up. I don't think you could have enough of the 20W bulbs to create enough PAR. The 150W floods might work, but the color rendition will be very poor. Color of light plays a big role in how we perceive both fish and plants.

As to PAR, many of us here use PAR meters to fine tune lighting. The Seneye meter is a popular one, which is widely used to measure PAR in both planted and reef tanks.

And when you are getting started with a planted tank, getting the light right is very important. Too much, or too little, can create problems. The amount of light should drive every other decision, including CO2 injection, fertilization, and selection of plants.

If I were you, I would look through the journal section here. Look for tanks that are successful in a similar style to what you have in mind. Then study their methods. It is easily the best way to have a successful start to your tank.

And you should start a journal detailing the set up. It's a great way to become involved with the community, and folks here are happy to offer advice and try to help you out if you need it.
 

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You mostly need the beam angle of the bulb.. height, and lumens and one can fairly easily do a guesstimate of it..
Cheap LUX meter off eek bay is a help..
If you disassemble the sensor on many LUX meters you will see it has a green filter attached to the photodiode..


Keep in mind "flood" and "spot" in commercial lights isn't what one would normally think of..

Actually your tank is fairly easy since it more like 2 24" cubes..

@ 2ft.. 60 degree lenses are recommended..

4000 Lumens each light x 2

Should get you around 160 "PAR" at the tank surface..

Pick high CRI bulbs >5000K and "yellowing" should be minimum.
Or crazy high >8000k

Like 8 of these:
https://www.1000bulbs.com/product/177401/IRT-10054.html

guessing around 40 "PAR" @ the 48" total distance..

Can't get cheaper than that.. ;) The estimate that is..
 

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Discussion Starter · #4 ·
Thank you guys for the responses!

I admit Greggz I have not seen a tank that is doing what I want to do and is successful. I have seen people use screw in lights but that comes in the flavor of "look at my new tank". I have no real ability to find out if it ended up working out or if they are actually running "high light" or not. They might be doing great, or it might have completely failed.

I really just had this idea and wanted to go with it. I figure that so long as I can get enough light it should be doable and I get to take advantage of off the shelf hardware store technology so it should be relatively cheap. This all brings me back to my original question of trying to figure out if its working or not. I figure if I put some bright screw in lights over my tank and turn them on, my tank will look bright. That doesn't mean I am getting good "par" values.

Thank you Jeff for the estimate, its definitely helpful as it gives me a starting place. I do however want more precision, I was hoping someone knew of a way to make it happen. I was thinking of taking apart a lux meter and getting rid of that filter and holding blue and red filters up over the diode and then adding the values together.. Probably wouldn't work but in my mind it was the simplistic way of trying to get an idea about par. Problem is that even if I did it I wouldn't know if it worked or not since I have nothing to use as a control.

I think I am back to buying a par meter. The seneye costs 150$ for the basic model. Is there anything out there cheaper?

Some possible bulbs I could use include but are not limited to:

https://www.amazon.com/Greous-400W-...ocphy=9007835&hvtargid=pla-609103501612&psc=1

https://www.amazon.com/ECOL-Outdoor...00w+par38&qid=1554078435&s=hi&sr=1-2-fkmrnull

And other similar bulbs.
 

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Your filter idea won't work well
Basic Seneye doesn't have "PAR"

first bulb isn't directional so thats pretty well out.
Second one will "work" if you go by my estimates except for this is not "best"

High CRI 80+
In many ways that's not "high" and you will be short red and prob. will look yellow-y in a tank.

BTW my numbers are more accurate than cobbling together a home made par meter..which BTW you'd need a real one in
order to compare/calibrate it..;)

Anyways, instructions:
https://www.rollitup.org/t/diy-par-meter-30-45.932412/

Doing it the accurate way..
https://www.apogeeinstruments.com/sq-520-full-spectrum-smart-quantum-sensor-usb/

Water proof version:

https://www.plantedtank.net/forums/20-diy/120109-diy-par-meter-yeah-you-heard-me-50.html

You don't need an exact reading, and even a PAR meter doesn't give you that. All it takes is slightly tilting the PAR sensor and the reading changes, plus there is an error range for the distance between the sensor and the light to consider also.
Ideally you will borrow a commercial PAR meter and calibrate yours against that, but I can understand that not being easy to do.
Hoppy
One more DIY..
https://www.plantedtank.net/forums/20-diy/823705-diy-par-meter-2015-version.html

 

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Just for fun I re-estimated those bulbs I linked to..




Increase the wattage as you so choose..
This isn't a reef tank so no need to go crazy..
For comparison:
 

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So I'm just going to point this out: you can post a thread asking someone with your intended light to get a par reading at certain depths. Might be a long shot but I think par readers are becoming a little more common these days.

Hell, a google drive sheet that the community can share would be great as well.
 

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Discussion Starter · #8 · (Edited)
Sorry for not responding sooner. I have been using the posts here as a means of educating myself on lighting to try and figure out what to do next. I didn't even know CRI was something I needed to be concerned with before seeing it here. Previously my research only turned up information on what plants need to grow, I had not considered that there was a measurement that essentially equated to plants looking GOOD to the human eye as well.

So to boil it down, I do not want 8 light fixtures hanging above my tank, that would definitely spoil the aesthetic. Going as high as 5 is not great, was hoping to keep it closer to 3 or 4. That meant I needed a much higher wattage of bulb but I also needed high cri. I eventually found what I was looking for... sorta. I discovered studio lights that come in 50w led varieties with something like 90+ cri. You can find a bunch of those here in case folks are interested:

https://www.bhphotovideo.com/c/buy/led-lamps/ci/24485/N/3943306111

These are designed for photographers and typically are hooked up to a light tent or umbrella.

They also are not really an option for me for a couple of reasons. 1) All of the powerful ones have fans in them. I am actually designing my entire tank to be silent or as close to silent as possible so putting lights with fans above the tank is right out. 2) They are not really cheap. I would need something like 6 of these which would make the bulbs alone cost something like 300 dollars. 3) I would prefer something more powerful so I wouldn't need 6.

So I went looking, and looking, and looking. Eventually I concluded that the combination of features I wanted simply did not exist in a screw in bulb. I could find bulbs powerful enough in lower color temperatures, and I could find them powerful enough in lower cri. I could not find them powerful enough in both high cri and high color temperatures.

Thats when I decided to switch things up a bit. In my research I discovered cobs and kept running into them in one variety or another when looking for bulbs. I decided I would build my own light fixture using COBs, a heat sink, and the reflector from an off the shelf screw in lamp. That way I can get the aesthetic of the off the shelf light fixture, but I can use the power of a DIY COB system. I am thinking I need around 18000 lumen at 90 cri 6500k to make my idea work. Running it through the calculators Jeff used I get 417.36 umol/s/m2 at the base of the light. I have no idea what that would look like 4 feet away and I couldn't find a calculator to estimate it but I am guessing/hoping that will work.

That means I need 2 of these critters:

https://www.mouser.com/ProductDetai...rknbu83yx7PpVbn5Yo/uV%2BcZ65A2QpC6mNrPt9gBg==

Having never worked with a COB before I have been researching how to go about building this thing. What I found is that I will need a heat sink, and driver (big ol power supply) to make this work. Some other fiddly pieces as well like a lens, a holder, some thermal paste, wire, some kind of means of hanging them, plus I will need to find a fixture reflector that will fit near enough to the heat sink that I can screw it all together. Drilling and taping the holes for the reflector is a non-issue for me.

What I haven't been able to find is information on what heatsinks I can use. Websites I have found suggest using heatsinks with 10 in2 of surface area for every watt. Well I have a 150 watt COB so that should mean 1500 in2 of surface area. Only that stat is not available when I go to pick out heat sinks. Nor are heat sinks sold by what wattage they can cool. Anyone know how to figure this out in a way that doesn't involve a ton of maths?

Edit: I realized after I posted this that my COB of choice may not work since I might need to buy 50 of the darn things to get my hands on it. So switching it out for this one will probably need to happen. It means a reduction in temperature to 5700k but an increase in lumens to more then 10k.

https://www.mouser.com/ProductDetai...rknbu83y%2BlrQIM/H7mNKlzte1GGiFYwuAtLBCpyDQ==

Second Edit: if using the second chip that should produce around 500 ppfd at the base of the light and use around 80 watts I believe per light.
 

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You might want to do some searches on lighting on this forum. Most of what your "discovering" has already been discussed at length here. It will save you a lot of time researching if you look at some of the research that has already been done.

I think an SB Reeflight freshwater 32" would be the easy way out.
 

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Discussion Starter · #10 ·
Thank you Kubla for the equipment suggestion. I am definitely aware there are off the shelf lighting units that will accomplish the goal of getting enough light down to my substrate. I am kinda re-inventing the wheel here because I don't like how they look. Flat boxes hanging over my tank is not what I am trying for. Ultimately I am trying to create a very industrial look. To that end I will be using some flavor of light fixture pretty far above the water, around 2 feet. As of now these light fixtures will be DIY COBs with off the shelf reflectors. The reflectors will not be COB reflectors but the kind you would buy for kitchen lamps or warehouse lights or some such. I will get the reflector after I have the heatsink in hand and can be sure as to the size base I need.
 

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FYI, you may be able to borrow or rent a PAR meter from the local power companies learning center. Here in San Fran you can go to the PG&E learning center and borrow a quality meter for a few days, for instance. Make sure to get the submersible one or you will have a hefty replacement fine.

Additionally, if you have access to a typical light meter that measures foot candles, use it and find a foot candles to PAR calculator online.



As for the lights, you may want to check out LED tape.

LED Strip Lights / LED Tape Light - Huge Selection!

That was the first link in my google search and is not a recommendation of their offerings.

Things to look for:
CRI >90
high lumens per foot
wet/damp location rating
CCT of 5000+ (CCT=color temperature)
 

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Heat sinking is a science and an art.. There are no shortcuts except ones own instincts and a bit of common sense..
surface area can b roughly calculated from the heatsink dimensions:
Except it can get complicated:


20sq inches for fines 2 sq inches for base plus change for small inter-fin area.. Not counting serrations also..
At the insanely impractical number you quoted that would be 2w 1 linear inch of that heat [email protected] 1.28 per inch..

48" is good for 96W..
https://www.heatsinkusa.com/2-000-wide-serrated-fin-extruded-aluminum-heatsink/
$61....

Bigger one is 48sq inces per inch.
4.8w x 48 = 230W.
Keep in mind this is all minimum estimated surface area..



As 2 COB's still push both Lumiled "fresh fish" and on the lower K end "crisp white"...
Not "the most" efficient COB's but color wise and some added bells and whistles (violet component in the crisp white) make them
ARGUABLY some of the best chips for our uses..
You will need to lens them or drop your height..
Note though that the reflectors that are recommended aren't err.. short..
See no matter what you do doing it lensless isn't a real option at 24"...

realy your option is either smaller many diodes or larger larger length cobs..

200gal high light, small emitter lensed array..runs at about 45% of capacity..
roughly the same heat sinks as the heatsinkusa w/ out serrations.


Yea complicated.. but hey user found it worthwhile..
Outside bars were 72W driven LEDs w/ roughly 70-ish inch 1" finned generic heatsink..but like I said not run full mostly..


FOR COB lenses look to the Ledil Agelina line of reflectors.
LDD-jh's for drivers
Meanwell 48V PS's..
All standard stuff..


Hmmm. didn't notice the industrial part..Tank above fits to a degree... ;)

Reflectors/cob/heatsink can look pretty industrial..



reflector comes in white too...


Book 3 demo with MechaTronix heatsinks, different COBs and holders, and Almeco reflector (left).
 

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Discussion Starter · #13 ·
Thank you Cmores for the suggestion! I definitely figured after all of this was setup I would find a par meter somewhere and to check if I was really getting high light or not. I had not even considered my local power company but its definitely on my list now!

Thank you Jeff for more insight! I feel like every time you post I am scratching the surface of some vast knowledge mountain. Some of the terms you used I don't even understand at this point. But what I walked away with was that I need lenses which I agree. The viewing angle for the cobs I selected is 115 degrees which at 4 feet up is way too large. I need to get it down to something like 60 degrees or thereabouts. I am glad to know I don't need such large heatsinks as I was despairing at finding anything that big. I read my formula for the surface area of heatsinks off of some random website which I suspect is either flat wrong or I managed to screw up my understanding of it. Either way it was not helpful. Once I narrow down my components I will just triple check everything to make sure it will work together. Thank you also for the lens website suggestion, I am sure it will come in handy once I figure out what sizes I need.
 

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Well it's not exactly wrong but its geared towards say someone building 100% on high wattagefactory light..AND strictly air cooling.

And as I showed you can get pretty good square inches w/ "trickery"..

Though one can go overboard. 10#'s of aluminum..
In fairness that is cooling a approx 74W custom led array and driver circuitry..


https://www.plantedtank.net/forums/...rainstorming-multichip-vero18-help-me-10.html

Oh easy beam calculator..
https://store.marinebeam.com/beam-angle-calculator-1/
There are some "details" about what the lens angle means..

BTW: you have 2 sort of choices.. Full coverage at the surface w/ the tank "training" the light to the bottom.. or concentration on bottom coverage.

Obviously there is a ton of in-between but the
First evenly lights the whole tank at the expense of PAR on the floor.
Second maximizes light on the floor at the expense of adding dark zones on the upper reaches..

I prefer full surface coverage since it bugs me if a fish swims up to the top and goes "dark" on me..
I mention this since you referred to 4ft measurement ..

Get the top right the bottom usually follows unless you have a goal..
This is really difficult to apply w/ REALLY deep tanks..
 

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Some random thoughts that might be helpfull, or not (especially without knowing what industrial look you are going for).

- I had a TEK 48" 6-bulb 19" above the rim of a 48"x 18 x 18 tank: a) those used fixtures are still around relatively cheap b) with a measured par of 1,000 at surface and ~150 at substrate it was not an easy tank to run c) with COB being a "single point of light" you get substantial shading, much more so with narrow lenses, meaning more of less powerful LEDS would give better spread

- the old ADA 150/250 metal halides + t5ho are pretty industrial looking
 

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Since there is plethora of light choices out there and sometimes things get missed..
If you are planning a, basically, single COB type setup consider "color tunable" COBs like this:
https://www.digikey.com/product-det...c/CTM-22-6527-90-36-TW01/1214-1553-ND/8324689

There not "the best" economically speaking but simplifies a warm white/cool white build..
https://www.digikey.com/product-det...c/CTM-22-6527-90-36-TW01/1214-1553-ND/8324689

You'd run 2 drivers per COB, 500mA each. (to not top out over 1.1A total per chip)
Prob average 27W per COB at normal operating conditions and about 2400 Lumens each
$18.28 per cob.

Easy sunrise/sunset solution to a "single" COB fixture..
 

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Discussion Starter · #17 ·
Thank you OVT for the suggestion!

I definitely considered doing some kind of LED Strip/Tube light in an old style florescent tube holder. I personally just did not like the look as much. If for some reason I can't make the COB solution work for me it is definitely my backup though.

And thank you again Jeff! You are right I was aiming at full coverage only at the substrate level. I will need to reconsider my plan of a 60 degree angle. Probably need something closer to a 90 degree angle to not get dark spots near the surface.

I looked up the whole sunset sunrise color situation to see what it was all about and found it to be a purely aesthetic issue. I admit its not something I am concerned with. My concern is having enough light at substrate to grow whatever I want both at the initial setup as well as into the future. Since the first COBs I posted are essentially unavailable unless I buy 50 at a time, my current plan is to get the 5700k cobs, these:

https://www.mouser.com/ProductDetai...rknbu83y%2BlrQIM/H7mNKlzte1GGiFYwuAtLBCpyDQ==

These produce just under 11,000 lumen at 90 cri each and should produce over 500 ppfd when two are combined at the base of the light. I am hopeful that this will give me enough ppfd at substrate 4 feet away to grow anything.

Soldering does not scare me but I have never put together a COB before so figuring out the terms for different things and making sure everything fits together is my current challenge. Each COB runs on about 82 watts (I believe) so cooling that passively will also be a concern.

These cobs are not my set in stone option so if anyone has a different cob that will accomplish the goal of having only 2 or 3 cobs two feet above water surface on a 24 inch deep tank and getting enough light to the substrate to grow high light plants, I am definitely open to suggestions. This is just the best I have found so far.
 

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https://www.luminus.com/products/cobarrays/entertainment-cob

Opposite problem.,high current

https://www.digikey.com/product-det...VM-27-56-95-36-AA00-F2-2/1214-1230-ND/4965750

Each COB runs on about 82 watts
CREE specs out at 54.3 @ 3A = 162.9W per chip. Will vary w/ junction temp. Using 85C here
You can run them at "any" (range) current you so choose..
Let's get it down to a reasonable 100w..around 2A drive current @ approx. 52v
That's the specs you need for the driver..
HLG120h-54A (non-dimmable but current adjustable 1.1-2.3A)
Max voltage out 54V (58max by adj possible) min 27V

dimmable driver (B) and you are "locked" at 2.3A (2.3 x53.3 = 122.6W per chip)
But, of course, dimmable effectively decreasing current
https://www.sager.com/_resources/pdfs/product/HLG-120H.pdf
https://www.digikey.com/product-det...MI9r-24Yu44QIV2f_jBx3G6A06EAkYAiABEgJTjPD_BwE
$50...

Crazy expensive lum-dev $80 chip
hlg 120h-36B
Since you don't need to "cut" the current might as well just get the B version..
3.4a x 33.5 = 113.9W
11,500Lumens x .88 = 10,120 lumens per chip.
https://www.amazon.com/PowerNex-HLG...hlg-120h&qid=1554438399&s=electronics&sr=1-12

rough numbers

Basically a $100 premium for arguably better and more uniform spectrum..90 vs 95 (both min) CRI

Rest of the parts are the same..heat sink ect..Actually only the chip cost is much different...

https://www.amazon.com/dp/B07GGP4HP...&pd_rd_r=19087423-575d-11e9-afa9-5fd63f932696
Just for comparison..

just as a mention;
https://store.yujiintl.com/collections/frontpage/products/bc-series-cob-400hs?variant=488243521
 

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Discussion Starter · #20 ·
If I was going to do the move to the 95 cri solution I seriously considered this one:

https://www.mouser.com/ProductDetai...rknbu83y1K8cRC5EIEFvY3el1FUptFs%2BteuEHu9Uw==

Which has an insane 24,000 lm. But near as I can tell its also a 300w light. It would be a little cheaper I think to just do 1 then to try to do 2 of the other 95 cri lights. That said, there is a serious disadvantage in trying to passively cool a 300watt light. Near as I can tell I need a heatsink that is a foot tall and a foot wide. Am I understanding that right?

Not having any idea about these things from personal experience, would I notice the difference between two 90 cri lights and two 95 cri lights?
 
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