I tried saltwater. i failed. but i alos tried to convert a freshwater 30 gallon into a salt tank. all worked well for about 6 months and then one night it went to crap. i'm not sure what happened. the water was clear as could be when i went to bed but when i woke up i could not see the back of the tank and all my corals were dead my fish were almost dead and i had bristle worms all over in the tank freaking out. still no idea what happened.
At the time, all I had were saltwater aquariums. I did a lot of SCUBA diving and worked with a pet store that sold saltwater. I'd go out diving with them to catch fish. We made a deal to sell on consignment what I didn't want to keep personnally.