Does anyone know what these lime green patches are on the sand?

[msavoy]

I can turkey baste the sand one day and then about 2 days later it’s back. My tank is about 6 months old. I used to have a brown type of algae on the sand but this is the first time I’ve seen green. Thanks for your help.

 

[Doctorgori]

looks natural to me besides green is better than red ....

 

[msavoy]

Ok great, as long as it doesn’t cause a problem, that was my only concern. Thanks for the info!