if you add all new water and all new sand you will have a mini cycle, but in your tank it should be ok. but since you have so ittle livestock, you may be better off getting a small cheap tank, or borrowing one, and make sure there is no major cycle. as for cooking the rocks, that can take a while, bypropsis is a b**** and hard to get rid of without cooking. to cook rock you would put it into a solid colored rubbermaid with a powerhead, and no light and let it sit.