| I would use this option last, as it will take you a long time to get through and then make the tank safe for fish, but I had this problem with a tank I was given by a coworker who had the tank in his basement, without fish, but with water, for about a year. The inside of the tank appeared to have 'rusted' (most likely from hard water) and was slightly brownish or tan. Putting water in the tank, even fresh, clear water, made the effect worse.
I made a mixture of Bleach and water at a 10 to 1 ratio. So, this tank was about 40 gallons and I added 4 gallons of bleach and filled the rest with water. The tank sat (covered because of the bleach smell) for about a week. The tank did not appear to be any clearer, until I drained it. The major tan or brownish color did come out, but there is still just a slight tint to it. I rinsed and rinsed the tank to get out the bleach and then let water sit in the tank with some dechlorinator. I ran that tank for about 6 months without any problems. The only reason I do not have it up right now is because I moved. |