Grey fuzzy growth on rock and sand

[Surfgirl211]

Hello,
I’m new to this group and aquarium keeping in general. We have a 32 gallon bio cube, with 1 clownfish, a GSP, a torch coral, a turbo, a trachus, and 3 nassarius.

We’ve been doing regular water changes and everything seems happy and healthy and growing, including what appears to be a moldy looking growth on the rocks and sand.

My water quality is pretty on point except the KH tends to drop.

Do I need to attempt to get rid of this moldy looking stuff. I have another clown in a QT tank that I intend to put in the main tank in about a week.

[Sniperhank]

I'll be honest, I don't really see what you are trying to show well enough to be able to give good advice on this.
If it bothers you, scrub it off with a tooth brush. Check flow in the area, if it is low things like cyano and other things can build up.