I see you trolling around the forums posting what seems to be newbie advice. You should considering referencing your sources, unless of course you figured out all this information on your own. You forgot to discuss saltwater surface tension is much higher than freshwater (which is why skimmers don't work for fw).
Sharing US Andrew's amazing fishes
Peppermint angels and Narcosis angel
His amazing reef tanks are filled with rare butterflies and angels! How did he do it without any ich problem?!