DIY LED Light Questions

[StirCrazy]

Originally Posted by Beanz

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