I would like to pick some of your brains about a 10g that I have. I've had this tank for at least 3 years and I've always had trouble keeping fish in it, except for 3 gold fish. I recently decided to give the affectionately named ToD (Tank of Death) another shot. I Chlorox-ed it, ran about 50 gals of water through it over the course of a few hours to get the chlorox out. Then I mixed up some gravel and threw into the tank. I have some gravel from a cycled tank which I put into ToD.
So, that was 3 weeks ago. I did 10% water change every week, I primed the water, put in some antibacterial and antifungal treatment just to be on the safe side. Then last week, I got 2 Ghost shrimp and a mystery snail. Nothing big. The bioload would have been roughly about 38%. Three days go by and the shrimp die. The mystery snail survived a little longer, but I took him/her out to try and save him/her. So, naturally I checked the parameters....everything is perfect. Like flippin' ideal for keeping fish in it. I just don't get it. I totally expected something like a massive Nitrite burst or crazy ammonia levels. Nope. Normal parameters. So.....any ideas? I was looking at the tank yesterday and noticed that it has a sealant on the inside, and I was wondering if it could be leaking chemicals that could be the culprit?