Underside of Sandbed turning red and grey. Worry??

[ReeferMaddness843]

So I was working in my fuge this eve and noticed the bottom of my Sandbed is turning this red and grey. It's about a 2.75-3" Sandbed. I'm assuming this has resulted from reflection of light from my fuge lid back to bottom of display. Should I "blackout" the bottom of the display or not sweat it? I think I'm going to blackout anyway just to be safe, just curious if anyone else has came across this issue?

 

[kacrocorals581]

Just different bacteria colonies is what I've always been told comes from deep sandbeds, I've had the same for years no adverse effects.

 

[ReeferMaddness843]

Awesome! Thx for input and advice!

 

[saltyfilmfolks]

Cyano likes light.