Algae ???

I'm not elf rally sure what this is looks like algae its in the sand below it in the glass. My wife pointed it out to me. Thoughts. Also how do you clean the sand the best way?

 

You leave that. It's ok. You don't want to release all of that into the water though. I clean the top layer of sand and then have to replace sand every 6 months. But that's just a sign of a healthy tank. You're good. But do clean your glass and and red algae on sand. I leave my back glass to grow algae which will turn to coralline
All good

 

Thanks!!! What's the best way to clean the sand??

 

I use a tube to siphon algae off top of sand. Other than that I leave it be. After 6 months I have to add more sand.