What Optics?

[Jaws]

What optics would you use if you had a DIY LED pendant that was mounted 10 to 12" above a tank? The tank is 30" deep as well.

[eli@fijireefrock.com]

Depending on the type and current LED s you are using.
for 3 watt or higher with at least 1 amp I would go with 90 degree lens as it gives it a nice spread.

[Jaws]

The tank is going to be sps dominant. Are 90's going to be enough for a 30" deep tank?

[eli@fijireefrock.com]

Originally Posted by Jaws

The tank is going to be sps dominant. Are 90's going to be enough for a 30" deep tank?

Depending on the LEDS and the current they are driven at..as an example my tank is 31 deep and running DIYs 100 w led running at I believe 4 amps 2 feet from the water line with some 60 and 120 degree lenses no issues at all having SPS.

[Jaws]

They're Cree's running at 1A and 1.5 amps between the royal blue and whites.

[eli@fijireefrock.com]

You should be good as long as you have enough of them over your tank ...either way I wouldn't go with less angle as it will give you as some say the disco effect.

[Jaws]

Where would you say the cheapest place to buy optics are? I'd need almost 200 of them. Too bad I bought 150 of the 40 degree angles originally.

[eli@fijireefrock.com]

Originally Posted by Jaws

Where would you say the cheapest place to buy optics are? I'd need almost 200 of them. Too bad I bought 150 of the 40 degree angles originally.

Send me the specs on you Leds as I will get a quote for you or send you directly to my supplier..

40 degree are ok but you need to mount those quite higher than the tank surface

[Reefer Rob]

I don't use any secondary optics on a 24" deep tank with the LEDs 8" off the water. Plenty of light for SPS all the way to the bottom. Tried 80 deg optics for the first 2 months, but didn't like the effect, too much top down light and not enough light from the sides. Corals look much better without the optics, and no "hot spots" or disco.