Adding more fish to quarantine tank

[Aquattro]

Originally Posted by AdamsB

I see no difference between this and having a mechanical filter.

Essentially, there is no difference, although a mature media filter can work faster than rock. And filter media can be re-usable once you're done with it. Rock, not as easily. If you've used medications, it may be too deeply adsorbed into the rock pores to remove. Foam blocks can be bleached and re-seeded. But, if it's a one off, you have spare rock, and it does the job, that's all that matters.