You should probably post your question in the general hardware forum or saltwater forum. You'll get more views and responses, not everyone checks the member intro forum.
For saltwater, you really want to use RO
water. A lot of grocery stores have RO
machines you can buy bulk water from.
For containers, any food safe bucket should be good, as long as it's not contaminated. #2 or #4 plastic totes, like the ones rubbermaid sells, can work well. If you're going to take the tank down, and move it in buckets, make sure the rock stays wet.