I have acquired a 29g tank from my brother. He was storing it in his garage for the last 3 years. He used the tank for a saltwater aquarium (fish unknown, he does not remember what he had). He claims that he discontinued the tank due to a black mold issue?? I did not realize that saltwater could have black mold inside the tank. (Forgive me if my knowledge is less than par). Now looking at the tank sitting in my living area, I am concerned that even with cleaning the tank out, and testing it for leaks, this may not be a good tank for future inhabitants.
So two questions:
1. Is there such a thing as black mold issue in saltwater tanks, or was he mistaken for an algae problem.
2. Because the tank has been out of commission for so long, is it still safe to use (after passing a leak test)?

Thank you for your advice in advance.

I think it is more like that it was an algae or cyano problem. I would clean the tank with a mild bleach solution and then rinse it well. You could include a dechlorinator in the rinse water. The bleach would kill any nasties that might be in the tank. Does he remember using any copper (for ich) in the tank?

I dont know what your brothers talking about. What he is calling "black mold" is anyones guess, but no it doesn't exist in saltwater tanks (mold doesn't grow under water). I think he is mistaking some other kind of algae, which is not harmful. Heck people eat alge...IE sushi wrapper.

If the tank doesn't leak a thorough cleaning with white vinegar and water should do the trick. The only concern would be if he used copper based medicines on his tank. This potentially cause an issue, but other than that CONGRATS on the free tank.

He said the fish were not treated for ick or anything. I am assuming from what he has told me he did not know how to properly maintain the tank, pH levels got out of control, and the only method of filtration was a hang on submerged filter which was not maintained well.

Anyhow, I will clean the tank with white vinegar mix, and see how well it does.

Like Carmie said, a weak bleach solution works also. I either case thorough rinsing with water is a good idea.

it sounds like a cyano problem to me also. good cleaning and rinse will work wonders. congrats.