Yellow slimy thing

[Naveed]

Need help in identifying this yellow slimy thing. How to get rid of this?. Now matter how much I clean this, it always come back. What cause this?

If I left it for a while it becomes like what is shown in pics.

Pics attached

Thanks

 

[Reefkeepers Archive]

That looks like a very thick and healthy growth of yellow sponge, harmless/beneficial filter feeders and a sign of a healthy and mature tank