LEDs Causing Algae on Sandbed

[wingedfish]

The fact that you are sure your problem is only do to lighting is probably keeping most from replying. Lighting plays a part, but only a part. You need to identify the problem. Pictures would help. Are there bubbles in it? Does it go away every night and build during the day? Copper in color sounds like dinoflagellates or cyano. Either way, manual removal and reduced nutrients is the proven method for either.