I am having problems aquascaping my aquarium. Right now I have a small amount of rocks in my tank, they are kind of rough and have some sharp edges and I recently read that this should be avoided (common sense huh?) I'm having problems finding rocks to purchase for my aquarium, lava rocks, slate, etc. I have looked at local fish stores but the rocks are very expensive, small and unattractive. I have slate in my backyard that I was going to use but when it gets wet it breaks up and I wouldn't put that in my tank for fear one of my fish will swallow a piece or it will be floating around my whole tank. Where do you buy your aquarium rocks from? Any suggestions would be a great help, thank you.