Do you need Optical Lens for you DIY LEDs Fixture?
- Thread starter maidia
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childress5tyler
Well-Known Member
I run a DIY without optics and my tank is 24" deep. I'd say if your tank is any deeper, use them but not necessary in a tank 24" or less
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Not necessarily, no. Depends on the wattage of the LED, what your keeping in the tank, do you want light to be stronger in certain areas, do you want it all over the place. Alot of deciding factors go into if you need Optics, and to what degree you need them in. Stunner Strips don't use them, and they work perfectly fine.
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maidia
Well-Known Member
Sorry I did not mention for the tank 120 gallon 4 x 2 x 2. The Fixture will be 10 - 12 inches over the top water. 3W each and 160 leds total. All SPS and lot of LPS on the bottom.
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childress5tyler
Well-Known Member
It also depends on how
Many LEDs you plan in running and at what intensity
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Many LEDs you plan in running and at what intensity
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maidia
Well-Known Member
I run 160 leds total. How big is your tank and how high is your led fixture from the water. Thanks.
I'd run em with optics. 65-85 degree.
roblox84
Active Member
You don't need optics, leds already have built in optics of 120 degrees. Just place the unit right over the water and don't hang it up 5 feet up like some do. I'm not using optics and my fixture is a foot up and still burning all my corals so imagine if I had optics.
jm23
Community Member
Hey Mai, 160 LEDs is craziness. I have 108 over my 265 gallon and they aren't running at full power. I personally think optics are a wise choice, without them you have too much light going outside your tank vs focused inside. I have a 30" deep tank and use 60 degree optics, they sit about 8" above the water. The unit is only 6" wide and the tank is 24" wide, but the coverage from front to back is excellent. I also have 6 red and 6 green LEDs that don't have optics in order to avoid banding / spotlights of red/green. Of course if you have 160 LEDs then you might not have to use optics, but optics will make your unit more efficient. Is this a current unit or one you are building?
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maidia
Well-Known Member
Thanks, I think so too. I did put the lens and the PAR is too high and look like it burn the coral.
I just renew all the cheap China LEDs to good LED chips, the coral seem pale. I did put the optics and too much PAR. I am going to take all out and let see. May be my nutrient is too low (Phosphate is 0 according to Hanna Checker and other test kit, Nitrate is unreadable by Lamotte test kit). I took 36 LEDs off and feed more and let see the color come back. Tonight I will take all opticals off.
Thank you all.
MaiDia
BeardedReefer
Community Member
This here is correct, to help you guys understand, if you put a center line on the led, its putting 60 degrees on each side, when you start putting optics on the LED's your turning them into beams instead of spread, at 7 inches off the water level you will have literally zero spillage unlike what jm23 is stating.
jm23
Community Member
Here are the numbers:
120° optics (60° coming off of center) equals 41.56" spread on the sandbed at 24" above sand and a 51.96" spread at 30" above sand. So one LED without optics will spread over 83" on the sandbed at 24" above the sand. Now that is one deep tank.
60° optics equals 13.85" spread at 24" above the sand and 17.32" spread at 30" above the sand. So one LED with 60° optics covers 26" at 24" off the sand.
I will stand by what I said above.
120° optics (60° coming off of center) equals 41.56" spread on the sandbed at 24" above sand and a 51.96" spread at 30" above sand. So one LED without optics will spread over 83" on the sandbed at 24" above the sand. Now that is one deep tank.
60° optics equals 13.85" spread at 24" above the sand and 17.32" spread at 30" above the sand. So one LED with 60° optics covers 26" at 24" off the sand.
I will stand by what I said above.
rajkovich207
Well-Known Member
I have no optics with 24 bridgelux LEDs (Chinese LEDs) running at aprox 40% whites and 65% blues over a biocube 29 (something like 20" deep) that supports 2 clams (maxima and crocea) on the sand and a green stag that has about tripled in size also on the sand. Sand is aprox 1" deep. Make sure you have full spectrum as its made a world of a difference. Other than that, the only downside I have is bleaching and large light spillage.
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maidia
Well-Known Member
Jon, good point but because this is DIY fixture and inside the canopy. I cannot raise the fixture higher. I did have 60 degree optics and look like they burn the SPS (pale), PAR reading is too high. I did take off the lens last night and the PAR come down at very good level. Let wait and see about few weeks or few months.
Low nutrient tank with lot of light, the corals will starving (pale color) that what someone told me.
Thank you all.
BeardedReefer
Community Member
What you said above and here is still wrong, if you actually do the math, with the law of sines you will determine that max spread of 120 degree optics at 24" off the sand in TOTAL is 24", the same at 30" off the sand bed in total is 30" of spread. Please actually do the math before throwing out false numbers. If you want to know how to actually figure this out feel free to ask. I'm happy to help.
jm23
Community Member
I dislike arguing over forums, but I feel the need to respond so that the truth is out there. What I posted is the math based on sines. That is why those numbers are precise and not false as you are saying. Here are a few links that will actually do the math for you if you are struggling:
Right Triangle Angle And Side Calculator
Triangle Calculator
Mai, I am assuming you do not have dimmable LEDs and as such it would make sense to either reduce the number of LEDs with Optics or to remove the optics increasing the spread. Either way you reduce your PAR which is the goal. You could always buy dimmable drivers, but you would also need some sort of controller. Also watch your ALK, if you have high alk, high light, and low nutrients that will lead to bleaching as well. I still have to swing by and see your tank one of these days.
BeardedReefer
Community Member
Didi you actually go to those links and input data on both? Because they contradict each other IE: they are providing two separate answers given the same input variables. So what this comes down to is you are incorrectly using the Law of Sines.
Try again Mulder.
