DIY Led question

[Ben2k4]

New to leds...
For my 75 gallon, do I need optics?

Specs
24 Cree Xm-L stars
24 Royal Blue Indus Stars

12 whites and 12 blues mounted onto a 5.9 x 12 heatsink
12 whites and 12 blues mounted onto a 5.9 x 12 heatsink

I read optics lower the spread a lot, so would this setup be more suitable without the optics or will the lowered spread be fine with the optics.

[killereef]

What kind of look are you going for( color Temp)? I recently just build a DIY LED myself for my 30 gal: 8 Cool White and 4 Neutral white XP-E, 10 RB XR-Tand 8 blue XP-G, 6 XML (High noon). When the high noon kicks on while the others are on, it has a 10k look. XML are really bright and if you are going for that 10k look then it would be find (IMO). If you are going for a 14k, you will need more RB. Rapidled and ReefLEDlights recommends a 60% blue and 40% white for a 14k look. I added 2 cyan red, 2 uv, and 2 green just the other day. I have ordered 2 more uv. Im running optics on mine 60, 80, and Carclo wide and medium. Im still playing around with the colors

[ghellin]

New to leds...
For my 75 gallon, do I need optics?

Specs
24 Cree Xm-L stars
24 Royal Blue Indus Stars

12 whites and 12 blues mounted onto a 5.9 x 12 heatsink
12 whites and 12 blues mounted onto a 5.9 x 12 heatsink

I read optics lower the spread a lot, so would this setup be more suitable without the optics or will the lowered spread be fine with the optics.

This will be very white most people feel a 1:1 ratio of XPG and XPE is even too white. XMLs will be very powerful.

[99taws6]

Most leds have a factory 120 degree optic. I have a 75 with mine mounted 5.5-6" above the water and I do not use optics.

[killereef]

I saw a mistake in my typing...XT-E not XR-T. My light fixture is 12 " off the tank and I used the optics to have lots of lighting on the sand beds. One thing to keep in mind if you have the fixture close to the water surface, think bout using a lexan splash shield or something like that. I have one fixture 20" above my fresh water planted tank and it does not have a shield, one of the led went out cause water got splashed on it. That one was connected in series and now I have a row out.

[Ben2k4]

hhmmm, so maybe I should go with a different led for the white... as I dont want it to be tooooo white. Or should I just add more royal blues? Opinions?

[Bluewater04]

At what current are you going to be running the xmls? For the chips you are running I would say that you would need 3:1 royal blue to white if the xmls are running at high current.

[SchnitzelReef]

just do a 2:1 ratio of blue:white and do dimmable if u can. Also in order to figure out what kind of optics u need, u need to know how high ur fixture will be mounted and how tall ur tank is