I've noticed recently that the white stones in my fish tank are starting to have something brown growing on them, which I suspect to be mold/algae. The mold/algae also seems to be slowly increasing over time.
- How do I remove the mold/algae?
- And how do I prevent the mold/algae from returning?
Edit
Here is a picture of my fish tank. We have a filter which you can partially see at the back. You can see that the white stones have some brown things on them, but interestingly it only happens on some of the stones. The fish tank also has several brown spots.