The wife and I took a road trip over to Mobile yesterday to look at a a tank owned by a man in a local forum. Its the first time I have seen a tank like this in person, not just pics on line, Awesome is all I can say. It is a 250g mixed reef tank with just about every kind of coral out there, maybe to many corals. He had corals behind corals behind corals, you really had to look to see all of them. He had SPS corals so big they were toching the front and sides of the tank and they were plating to the glass. I was going to ask him why he didn't frag some of the corals, but the answer was apparent, he had no place for the frags. He had a 20g and a 40g frag tank that had no more room for even one more frag. Anyway, it was an awesome tank, and I was really impressed. He told me when I was ready he would make me a deal on a frag pack to get me started. He was using something that I wanted to get your thoughs on though, never heard of it. He had a piece of equipment he was using, looked like a Kalk Stirrer with out the stirrer, he was using it like a reactor. What he was using was a pebble type stuff in the reactor and he said it was supposed to help reduce Nitrates in the tank. Anyone ever heard of this ( I am sure some of you have) and does it work??