First Saltwater Tank Questions

[versatile bread]

Hello!
I am a total novice when it comes to saltwater tanks, but I have been keeping tropical tanks for about 6 years. I am wondering how often I would need to measure salinity in a 30 gallon breeder (although I may buy a bigger tank if it would make it easier to manage water quality.). I am also wondering how sensitive fish and coral (I am not sure I will do corals yet) are to changes in salinity. Finally, would an auto top off system allow me to leave a tank for a couple of days, while I am out of town, which happens often, and the main reason I have not put together a marine tank yet.

Thanks for Helping

[Sniperhank]

ATO are great. You can set it and forget it in terms of your top offs. Some fish and coral are more sensitive to this than others, but in general it isn't a problem. I'd suggest looking through our articles section to get you started on the right track.