Adding Rocks from a Different Tank
My brother gave my son a half dozen rocks that had previously been in a 55g cichlid tank. He pulled them and had them sitting out for about a week. My son wants to put some (all) of them in his 36g tropical tank.
Here's what I've done, but please critique:
I tested the rocks w/ vinegar (just to be sure). We then washed the rocks in tapwater. I've now submerged all of the rocks in a 5g bucket filled with water from our last water change, and I dropped an airstone in to keep the bucket water moving.
My thought was to let them sit in the bucket for a week or so before transferring them into my son's tank.