DIY LED Light Questions

[Beanz]

Hi all, so i want to build a LED light fixture for my new 45 gallon tank. I have now decided that i want to keep SPS corals in the tank. I don't really know all that much about the PAR, lumen, lux stuff that the SPS will require or how to achieve these amounts with LEDs. Anyways i will come back with more questions but if someone could please explain these things to me that would be very helpful.

Thanks, Ian

[Cal_stir]

check reef central, there are some good build threads there, lots of info, i built one for my 90

[hillbillyreefer]

Check out Ron99's build thread on here. Lots of good tips.

[Beanz]

Well i was thinking of buying a combination of CREE XR-E G5 Cool White and CREE XR-E Royal Blue how many would i need of each like what is a good amount of each to combine with each other and also what optics should i use? (would using optics enable me to use less LEDs?)
My tank is a 45 gallon tank that is 18" tall(but the water is only about 14 1/2" deep due to the sand depth and stuff), 12" wide and 48" long.

Thanks, Ian http://www.rapidled.com/images/store_version1/pixel.gif

[NanoHuman]

I custom built a CREE system like you are describing and although I ordered a whole variety of optics, none of them work on my tank. The water is 14" deep, and I believe you really have to get over 20" to have the 40 degrees as a requirement for deeper penetration.

Since your tank is quite long you may want to utilize some 80 or 60 degree optics for spreading the light out, or use a lot of LEDs.

I would recommend Nano-reef for learning how to build the system. Evil has many posts there and the documentation is excellent.

[Twinn]

Just another thought if you are going to order the LED lights. Both the Vertex LED fixture and the new Aqua Illuminations light are now using a combo of white, royal blue and blue LED's.

[Beanz]

Thanks guys. So do you think that 13 CREE XR-E G5 Cool White and 13 CREE XR-E Royal Blue with 80 degree optics would b enough to keep SPS (More or less of which lights or is having the same amount of each type beneficial for the corals?) Also the light would be more at the back of the tank where the SPS corals would be, so like an 8" area. Cause i wanna have some swimming room for fish at the front of the tank. I don't have a very large budget probably $400-$500 so would more of the whites b better or would this 50% blue 50% whites work well?

Thanks, Ian

[Cal_stir]

i built a led lt for my 90, 2 48in x 6in heat sinks welded together, 36 cree xpg cool white, 27 xpe royal blue ,9 xpe blue, 6 eln-60-48d drivers, diy sunset/sunrise simulator, no optics, lt @ 1 in above tank, glass canopy, tank 48x16x24high, driving the whites @ 1300ma and the blues @ 900ma, the penetration is good, the distribution is good, and it shimmers, it is definately brighter than my Current USA 4xt5 ho 4ft fixture, i am lps dominant with some sps, all are doing well. you definately should use the cree xpg and xpe leds, i got mine from cutter electronics in australia, got free shipping and $30 COD for taxes & brokerage (before HST), got my drivers from rapidled and they do sell xpg but i don't think xpe. i am new to this forum and not sure how to send pictures. all my leds are bin 5. this link has a few pictures, it is post #34
http://www.reefcentral.com/forums/showthread.php?p=17418032&highlight=cal+stir#post17418032

[Beanz]

Ok thanks Cal

[Beanz]

Ok so i was looking on rapid LED and i think that imma just get the 24 LED kit with dimmable drivers i'll order it with 80 dsegree optics, and then i'll get 2 23" heat sinks and 92mm vantec stealth fan kit. while i work more to get money i'll build the fixture, what would be a good design and what is a good material to build it outta? i was thinking of designing the fixture so that it its on the inside rim of the tank so it will have enough weight that my eel won't get out. (atm i'm using ziplocks with sand, not all that attractive of and appearance ;)) Anyways what r ur guys' opinions on this and also about the fixture?

Thanks, Ian

[Cal_stir]

are u using the fixture as a cover? saltwater and aluminium don't mix to good, you will have a lot of corrosion, aluminum angle or square tubing are good for frame, dissimilar metals will corrode as well so keep it all aluminium.

[Beanz]

Naw i'm using the the fixture to hold down some acrylic sheets that i already have on top of the tank (should i cut some spaces in the acrylic and buy some fans to mount is in it to get more airflow over the top of the tank water? or will a 10 gallon sump with a coralife ss 65 gallon and 10 gallon refugium b enough for gas exchange and such?), ill probably raise the fixture up maybe 4-6 inches and hold the acrylic down and keep the fixture propped up on some 1X1 struts. I think for the fixture imma use L channel aluminum and put the heat sinks in the L, then i was thinking of screwing the L channel onto a 2X4 than putting the same stuff that's on my stand. But before i will cut squares in the side of the wood so i can mount the fans in there. Is this wise to mount the aluminum to the wood? or will it get too hot?

Thanks, Ian

[Cal_stir]

don't cut the sheets, you will get enough gas xchange with sump and skimmer,the fan will keep the heatsink nice and cool, the leds will fail before the heatsink gets hot enough to set wood on fire

[Beanz]

ok thatnks cal, i am gonna do a water test today and c if the pH is changing as a result of the sheets. if there is i might get some screen but the acrylic is doing a dandy job of keeping the zebra in the tank. I am going out today to get the materials for the fixture so i will start posting pics today maybe, i might get a shot of the zebra too if i can get a good shot :D

[Beanz]

Ok I built the fixture, but have not added the peices for how high it is gonna b. So how high do u guys think I should have the fixture, and should I use 80degree optics for the height or something a little more focused if the fixture is higher.

Thanks, Ian

[Cal_stir]

my fixture is 1 inch above tank with no optics, the leds emit @ 120 degrees without optics, i find this to be perfect for my application, no spotlighting. i remember reading an article about a guy who used 40 degree optics and he had to mount his fixture about 12 inches above his tank to eliminate the spotlighting effect, my guess with 80s would be @ 4 inches.

[Beanz]

Ok I will try that out, do u think that the 24 LED with dimmable driver kit will be enough light for the back of my tank (6") or would it b better if i saved my money and bought the 36 Led with dimmable driver kit?

[Beanz]

This is a little off track but this is my new little zebra eel :love: and thanks for the help, please keep the info coming it is really giving me ideas and an understanding of lighting. O and i need to get some calcium additives and a test, if i get some Kent Marine Liquid Calcium do i need to dose kalkwasser? I am looking to keep SPS near the top of the tank and LPS near the bottom.

Thanks, Ian

[fkshiu]

Contact Ron99 on here. He's built his own DIY LED fixture that's already spreadin' the PAR wealth.

[Ron99]

Ian, figured I would continue answering your questions here instead of by PM. I think for your sized tank you will need at minimum 48 LEDs with 80 degree optics to provide sufficient PAR for SPS corals. Personally I would go with 54 to 60 LEDs. For comparison, I used 80 LEDs with 60 degree optics on my 48" x 18" tank in 4 rows of 20. I am currently running the blue LEDs at 100% and and the white LEDs at about 80% and have around 500 to 600 PAR 1/3 to 1/2 the way down my tank which is 20" deep.

With your tank being 12" wide rather than 18" you could drop one row and do 3 rows of 16 to 20 LEDs. The more you do the higher the PAR will be. With 24 to 36 LEDs you will have to run them without optics and may not have sufficient PAR for many SPS.

[Beanz]

Y would I have to run then without optics if I only have 24-36 LEDs?

Thanks, Ian

[StirCrazy]

Y would I have to run then without optics if I only have 24-36 LEDs?

Thanks, Ian

because you will need the full 120 degree spread of the LED to cover the area. if you put 80 degree optics on on with that few LEDs you wont get good coverage and you can get spotlighting and it will look bad.

Steve

[Beanz]

Ok so i thought about the set up (lol woke up this morning and couldn't go back to sleep b/c i was thinking about it :D). Anyways i was thinking that i could just get constant current drivers i was thinking Mean Well LPC-35-700W for the blues and then i could still get the same amount of cool whites with dimmable drivers and use them at 700w or higher if it still looks good. Then i will probably b able to get a total of 48 LEDs, anyways just a thought. What do you guys think?

Thanks, Ian

[Beanz]

because you will need the full 120 degree spread of the LED to cover the area. if you put 80 degree optics on on with that few LEDs you wont get good coverage and you can get spotlighting and it will look bad.

Steve


Ok, do you think that if i just get the 36 LEDs and raise the fixture up, 4 inches like Cal said (maybe higher if spotlightinf still occurs, or would this reduce PAR too much?), this would eliminate the spotlighting and work for keeping SPS closer to the light and LPS and maybe some softies near the bottom of the tank?

Thanks, Ian

[StirCrazy]

Ok, do you think that if i just get the 36 LEDs and raise the fixture up, 4 inches like Cal said (maybe higher if spotlightinf still occurs, or would this reduce PAR too much?), this would eliminate the spotlighting and work for keeping SPS closer to the light and LPS and maybe some softies near the bottom of the tank?

Thanks, Ian

I tent to agree with Ron, that at 36LEDs your not going to get the coverage. I was looking at 48 LEDs on a tank that was 30 long x 12 wide. with 40 degree optics. you have a tank that is the same width but over 1.5 times longer so with 40 degree optics that would put you at 72 LEDs with 40 degree, you can go a little bit less each time you increase the angle of your optics so 60 degree you could get away with fewer and at 80 degree even less but I would think that if you did 3 stagered rows at a spacing of 2.5" you chould be good with 80 degree optics, so that works out to 3 rows of 18 which is 54 LEDs. the problem is you don't want to build your system and find out you don't have enough as then the only option is to remove your optics and decrease the PAR or lift them and decrease the PAR, so this is a case where it is better to have to many than to little. you might be able to get away with a 3" spacing with 80 degree optics.

I think the best way to determin what you like is to get 6 blue and 6 white LEDs and 1 mean well driver. get a scrap chunk of heat sink about 36" long and 2" wide (1/4" hunk of aluminum will do as this is a test only heat sink) drill holes at a 3" spacing and wire them up. put it over your tank at night with the rest of the room dark and look at the effect. try 60 degree optics, 80 degree and no optics and try to determin where you get spot lighting. you will be able to reuse everything except the optics you don't like and the temp heat sink so you will be out maybe 20 bucks for testing.

if you get an even blending of color at 3" spacing then you are good to go. if you get spotlighting then re drill at 2.5" spacing and try it all again and see how it looks. this will tell you exactly how many you need with out trying to guess.

once I get my shop finnished, I am going to do this and conduct some testing including looks and PAR out puts at different spacing with different optics, only problem is it will probably be next year befor I can even think of doing ti because I have to save up another 5K to finnish the inside of the shop and heat it.

as for your ballasts, I personaly would put dimable ones on all the LEDs. not a lot more money (under a 100 bucks for the whole setup) and give you a lot more ability to do different things. you could later ass a andruno based controler which would gradualy fade all your lights in and out for sunrise/sunset, ect. with blues stuck at 100% all the time then you would have a bang of blue light and the white would gradualy fade in. also for new corals it would be nice to be able to dim the lights to 50% for a day or two then increade them in bits over a week to prevent bleaching of new corals.

Steve

[Ron99]

Ok, do you think that if i just get the 36 LEDs and raise the fixture up, 4 inches like Cal said (maybe higher if spotlightinf still occurs, or would this reduce PAR too much?), this would eliminate the spotlighting and work for keeping SPS closer to the light and LPS and maybe some softies near the bottom of the tank?

Thanks, Ian

I would say no. The reason for more LEDs is not only for even coverage and colour blending but because the overlapping output of the multiple emitters adds up to the amount of PAR you want. I did a quick experiment measuring PAR output of single emitters driven at 350mA at a distance of about 3 inches from the LED and no optics. A cool white Cree XRE put out about 176 PAR, a SemiLed cool white (about a middle of the road bin, not the highest brightness bin) put out about 100 PAR and a cheap generic chinese white LED put out about 50 PAR.

So even with say a 60 degree optic you will probably have no more then 350 PAR at 3 inches from a single emitter. You need the light from the LEDs to overlap to add up to the PAR you want if you want to get up to 500 PAR for SPS.

For further comparison, a 12" AI module uses 24 Cree XPG and XPE emitters to give the high PAR numbers it produces. You would need 3 to 4 modules to cover a 48" tank so that would be 72 to 96 LEDs.

Unfortunately, if you want a high output LED fixture there are no shortcuts and the up front costs are relatively high. But you will save in the long term by not having to change bulbs for 6 to 8 years, using less electricity, and putting less heat into your tank so you may not have to run a chiller or fans etc. (my tank stays between 78.5 and 80 degrees depending on the ambient temperature. During the heatwave it went as high as 81.5).

[Ron99]

Forgot to address the drivers. You could go with the non dimming drivers as you suggest but as Steve says you won't be able to do nice sunrise and sunset effects or adjust colour temperature or change things for acclimation purposes. If you don't care about that and just want to have the blues come on at a set time and then the whites come on at a set time you could save a bit by using non dimming drivers for both. But the cost difference for dimming drivers isn't that much more and gives you more flexibility for the future.