I have a 15 year old aquarium tank which hasn't had water in it for more than 10 years. I recently decided to fire it up again, thought I did all the right things re filtration, gravel cleaning, water testing etc before I bought some gold fish. Within a day or two the fish started to die.
The aquarium is situated outdoors but in a sheltered gazebo (no direct sun light). Temperature variations is a worry but I run a chiller as well as heaters and manage to keep the temp between 25.2 and 26.1 degrees over any 24 hrs period. (like I said, gold fish...) A fluro is timer controlled to be on for 12 hrs during daylight hours.
I took sample of the water to my local pet shop. They confirmed that the water met all requirements re ammonia, nitrate, PH etc. The temperature was monitored and confirmed fine.
The pet shop experts are as confused as I am as to why the fish die (I have bought 4 lots of fish over the last couple of months and all have died within 5-7 days.
The water is clear, there have been no insecticide or similar sprayed near the tank. I have varied the food (newly bought), neither over fed, nor underfed the fish (I hope...) Monitored ammonia levels daily!
I was running out of ideas until a friend suggested "is it possible that the sealant holding the glass panels together, give off some undesirable poisons"? (apparently aging sealant has been known to cause problems in 'other areas', including giving off poisonous substances)
I would really appreciate any thoughts on this issue. I hate the idea of giving up on my aquarium but feel awful about killing the fish.
Kind Regards with a cry for HELP!