ok im stepping into the darkside of fish keeping for the first time. i have rwellbaum that has kept salt water before but as for me i have alot to learn. im in the middle of trading my jetski for a 72 gallon bowfront with lots of corals and live rock. comes with top of the line lighting and a 30 gallon sump also with lights. fish are clowns and snails and a few others i can not remember off hand. anyway i was wondering after doing research everyone is RO water this and RO water that can i use fresh water and add marine salt or what and Also included in the sale is a Reverse Osmosis set u.how does that work. well i need to learn so some one tell me what i need to know so i am no longer ignorant. thank you