I used it a few times and it polished off the water nicely. I took it out however b/c i was concerned it was leaching out all the trace elements from my water. is this a concern for any of you, in particular SPS keepers? i have a lot of calupera in my fuge, and am thinking i should keep carbon in there all the time. any thoughts? also how do people replenish traces elements? water chanages, additives, etc.. or is this over rated? thx in advance!!