90/120 degree optic lens

[JohnnyD88]

which lens is better for 30" deep tank 90/120 optic lens ? i'm building a 48" led fixture from china the bran is APOLLO 20 and is 650W. so i want to know which optic lens is better for tank. that bottom attachment is my led layout

 

[MrX]

The deeper the tank the tighter you want the 'beam' of light so it penetrates down more; so the lower the number the more focused it is. I'd think 120 would spread the light too much, 90s might even be too much.

 

[JohnnyD88]

so u think 90s wouldn't penetrates to the bottom of my tank ? my tank will be dominate with SPS. so u think 60 degree optic

 

[nixapatfan]

Optics will depend on how high you plan to mount the lights. Just cut out a piece of cardboard at those angels and see where the light will go. Too narrow and you might not get enough spread at the top.

 

[Privateer]

It will also depend on how high off the water the light will be. I use a combination of 90 and 120 for my DIY light but it is about 2 inches form the surface. If you plan on hanging it, do as nixapatfan said and evaluate the light spread using cardboard cutouts. From what I can of the design, it looks like 60 (for white and blue) and 90 (for other colors) combo would be better.
BTW it's a pretty sweet design with a ton of power! Can't wait to see the final result.

 

[JohnnyD88]

this is the final led layout, so can't wait for my light to arrive in 2 half week . The light will be 9" above water i decide go with the 40" fixture instead of 48" because i will get alot of light spill on the 48". thank for looking and input guy and girl

 

[dz6t]

How big is your tank that needs 650w of LED?

 

[JohnnyD88]

my tank is 150 gallon extra high and 48''long 24''wide 30'' deep soon will dominate with SPS

 

[dz6t]

I will consider the type of LED chips to use before lens. Actually, LED's major issue is the lack of spread, using lens will just make it worse.