Has anyone used local gravel in their aquarium? There is a feeder stream to a large creek about 45 minutes north of my house with large gravel bars in several locations. I would like to use this gravel in a 125 gallon South American tank that I hope to have installed and ready to stock in about four months. The gravel in this area has a nice mix of colors ranging from green to blue, and cream to dark brown. I want to screen it down in size for a range of 1/4" to 1/12", simply because I already have classifiers in that size. The water quality appears to be quite good and I dont know of any pasture of agricultural run off for the feeder steam. This is the head-water for our local drinking supply and drains from a large forested area. I figure I could bleach it to kill off any unwanted critters and then re-establish the proper bacteria once its in the tank. I intend to run some tests once the weather warms up. I know that we have large limestone deposits further north of this location but this looks to be mostly sandstone, with some mudstone and shale. Would this work for a South American biotope stlye tank?