Are you using this for Freshwater? If so WHY?? You can get play sand which needs rinsed for hours or pool filter sand which about 5 times rinsing will work much better. Plus it is half the cost. Play sand can be bought at Home Depot or Lowes. Pool filter sand can be bought at any pool supply store. I prefer the pool filter sand because it cleans so much easier.
I personally would not use it. If you are looking for a particular color you can always check out estes color quartz which is safe to use in fish tanks (I use it along with 3M quartz). They provide a variety of colors so you can always mix or pick one. It can be found at a local construction store usually. Just a thought.
It shouldn't, it has not effected anything in my tank. It would be like using any other substrate in an aquarium. Its pretty much the stuff they mix in the pool cement to give the cement different colors in it. Its used for other stuff as well. It feels like sand though. If you get it make sure to wash it out first (you would have to do this with any sand). Also it will come in two different grades (one grade is smaller and looks like sand and one is a bit larger almost like smaller gravel so you can pick which one you want).
Here is a thread with someone else who uses it in their tank: