Eco-complete is good, nutrientwise, but be careful you don't get a bad bag. I've had a neverending problem of "dust" floating in the water that I completely attribute to the substrate--I'm not the only one with this issue. Also, it can raise your pH and hardness for a little while, but supposedly that should subside. OH ALSO-I expected it to be black, as I've heard, but it's always been brown.