What equipment is needed for a saltwater aquarium?

[isaidme]

Hello all,I would like to setup a saltwater aquarium for the first time and am unclear
about the basic equipment needed.I have a few items on my list that im interested
in and could use opinions on.Im looking at a SeaClear 30gallon tank with a Eclipse3 lighting and filtration system,and a 150 watt submersive heater.One of the local fish stores told me to use a undergravel filter but then another told me not to also crushed coral was suggested.What am I missing here guys equipment
wise?Thanks

 

[Corp000085]

I don't know anything about marine systems, but my best bet would be to research the best salt for your system. I don't believe that the filter or heater really matters too much, as long as its adequate for your tank size

 

[isaidme]

Thanks for your reply,Im thinking now this might be the wrong place for my question,sorry moderator's!