Sand bed potential problem

[coraline79]

I have a very shallow sand bed in my main tank(125g), about 1-1.5 inches. Under my tank I have a pretty large refugium with many different kind of macro and Mangroves, and I run a dual 10k T5NO light fixture 24x7. Well last night I was staring at my fuge for a while watching all the tiny creatures, and I looked up to notice the bottom side of my main tank sand bed is not white anymore, it has splotches of green, pik, red, and so on(algae i guess) just above the fuge. Is this bad? Should I put some sort of cover over on the bottom side of my tank?

Thanks for the help!

Joe

[Troutmasters02]

Picture is always helpful, but it sounds like algae inside the main tank. Since you have a thin sand bed I bet the light from each side of the glass is enough to grow some colorful items. IMO don't worry about it.

[MKCindy]

Yep, it is normal. If you don't like the look, you can alternate stirring up just a little of the sand bed at a time. Just don't overdo it all at one time, there are critters living in there too.

[coraline79]

I am not concerned with the look. The sand looks completely normal on top side in main tank, it is when looking up from underneath the tank that you see these algae blooms, 3 foot long(half the length of the tank). I have had other tanks running for over a year without this happening. This is in the bottom of the sand bed.

[jroescher]

It's 'Live Sand'!