>Thanks for your reply. I'm thinking that there may not have been enough >circulation in the tank (Eheim cannister filter). When I took out the >driftwood, it smelled like sulfur. This may have collected in the substrate >which is 3-4". The tank has been set up for 3 months beofre that it was a >Tanganikan tank. I will give what you said a try, that is test out with some >less expensive fish. >Thanks again. Andy, I really don't do Tanganikan's but from what I have heard they require hard water. If you were using the Eheim and gravel I would probably take them out like you said. (Or seriously clean them out.) It probably doesn't matter but I, myself, would have felt safer especially switching to a soft water world. With my apistos I only used about an inch of fine sand, plants, pots for spawning and Hydro-Sponges for filtration. I did 25% water changes ever 2 weeks. (I found that waiting 2 weeks usually brought my breeders into breeding.) Your tank may have had a high pH buildup from the previous 'tenants' even though you made it a soft water tank. Did you add chemicals to the Tanganikan tank to make it a high pH and harder water? If so there may have been some still lingering in the filter and gravel so that the fish built up a tolerance to the pH going up again and then when you did a water change the serious drop in pH (to them) may have done your new 'borders' in. Just a speculation. I hope this helps. Kaycy