Need help with led lighting

[shibbyplustax]

I am about to order a led light online but im not sure what kind of lens to order.
This is a 120w wingoled super d120 for my jbj nano 24 which is 18x19x20 i believe.

I have the option of choosing either 60 degree majority or 90 degree majority.

What do these numbers even mean? I am guessing it it the direction in which the light is emitted but i am not sure.

Which one will be best suited for a tank like this?

 

[shibbyplustax]

Here is the fixture http://pages.ebay.com/link/?nav=item.view&id=170890340067

 

[Koyfam16]

Wingo is a vendor on here. You can contact him.
90 degree will give you more spread while 60 will be more concentrated.

Sent from my SGH-T959 using Reefs

 

[Imbarrie]

20 inches deep you may not need any optics.
They are nice to have if they are removable you can take them out.

If you get a lens that will focus light for coral on the sand you may burn any coral sitting higher on the rock.

 

[shibbyplustax]

20 inches deep you may not need any optics.
They are nice to have if they are removable you can take them out.

If you get a lens that will focus light for coral on the sand you may burn any coral sitting higher on the rock.

Good point. I have to check with him if they are removable. I do plan on mounting it above the tank tho.