Hi, I have a small problem (nothing major) with one of my tanks. I want to start up a new tank, so in doing so I am taking rock out from a previous tank which I just ended. My problem is this; the rocks have a lot of algae growth on them, very orange like substances growing on it. I have tried scrubbing these rocks with a toothbrush and boiling them and everything but to no avail. The problem is also that the rocks are very rough with a lot of crevices which I am not able to reach just by hand brushing. I would like to know if there are any other methods to clean off these rocks to get them looking like new again. Any response would be greatly appreciated ! Thanks.