Hi, I have just inherited a 36"X12"X12" tank fully equipped with 2 internal filters, 2 gallons of white sand, an assortment of rocks and bogwood although I have owned tanks in the past, they have been purchased from new, can some one advise me if i need to replace the sand as well as the filter media, although the smaller of the two filters has new media ready to use, by the way this stuff has sat in a cupboard for appox 6-8months.