Distance from water to light

[nfored]

What is a good distance? I have them about 24 inches above the tank so I can access the tank for feeding and what not. but I am starting to think this might be to far away. I currently have no top on the tank, and worry about having the lights to close and having water splash on them. I will be making an acrylic top for the tank soon and then I can lower the lights to about 3 inchs above the tank if need be. thoughts please.

The light is a quad lamp 4 foot T8 fixture.
2800 Lumens
32 watts
6500 Color
85 CRI

Tank
48x16x12

 

[I<3fish]

They should be close if you have a top but yeah like you said that works till you get a top.