how do you tell the difference from to much light bleeching and UV ray sunburn?

[delta410]

Anyone have a picture of the two, or a really nice description of how to tell the difference?

Got a Double Ended bulb over my tank and wondering if it's leaking out UV rays or it's just to much light. Yes, I'm running glass under it but don't know forsure if it's catching the UV's.

 

[Amphiprionocellaris]

Very generally, bleaching turns the corals white (or lightly colored, though some cases will actually result in color intensity increasing as brown zooxanthellae leave the coral). UV burning, on the other hand, tends to cause tissue recession immediately (whereas the coral lives for some time after a bleaching incident). Given the relative rarity of UV burning compared to bleaching, I would say that any trouble is likely bleaching. However, I wouldn't automatically say it's a light issue (and even then I wouldn't know immediately if it's too much or too little), because there are just too many variables.