So I've had my tank up for about 10 days now, no fish. The tank water smells like chlorine, basically like swimming pool water. No idea what the chlorine source could be. Tank is used, I have pool filter sand in it and I've put in a few of the rocks that came with the tank. Should I just keep changing the water until it's gone? I'm wondering if the previous owner cleaned anything with bleach or something at one point; I got it off of craigslist and didn't keep the guy's number. Could the PFS be to blame? I don't think so, since I don't remember any chlorine odor when I rinsed it.