I'm currently using it. I've only done one water change with it, although a big one, and everything went well. It's supposed to be good in that it's high in the elements we want, like alk,ca, etc. If you do change, just make sure you go slow. Sometimes the tank doesn't adapt too readily. HTH
I was planning on using it on my FO tanks so the impact shouldn't be that bad. I figure for the price it's worth it as when I do water changes they're some what large.